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CBSE 10TH Science
Science
Class X
(CODE NO:086/90)
- As per CCE guidelines the syllabus of Science for class X has been divided term wise.
- The units specified for each term shall be assessed through both Formative and Summative assessments.
- In each term, there will be two formative assessments each carrying 10% weightage.
- The summative assessment in the first term will carry 20% weightage and the summative assessment in the second term will carry 40% weightage.
- Hands on practical examination will be conducted through formative assessment once in every term with 20% weightage of total term marks.
- Assessment of Practical skills through MCQ will carry 20% weightage in every term end summative assessment.
COURSE STRUCTURE CLASS X
| FIRST TERM | MARKS-80 |
| UNITS | MARKS |
| I Chemical Substances
Chemical reaction; Acids, bases and salts, Metals and Non Metal |
29
S |
| II World of living
Life process; control and coordination in animals and plants |
19 |
| III Effects of current
Magnetic effects of currents |
26 |
| IV Natural Resources
Sources of Energy |
06 |
| TOTAL | 80 |
| SECOND TERM | MARKS-80 |
| UNITS | MARKS |
| I Chemical Substances
Carbon compounds; Periodic classification of elements |
21 |
| II World of living
Reroduction; Heridity and evolution |
27 |
| III Natural Phenomena | 26 |
| IV Natural Resources
Conservation of natural resources; the regional environment; our environment |
06 |
| TOTAL | 80 |
Science (Chemistry , Physics , Biology ) Syllabus 2010 - CBSE Class X
COURSE STRUCTURE
CLASS X (Theory)
One Paper Time : 21/2 hours Marks : 60
Unit Marks
I. Chemical Substances 18
II. World of living 16
III. Effects of Current 10
IV. Light 8
V. Natural Resources 8
Total 60
Theme : Materials (55 Periods)
Unit 1 : Chemical Substances - Nature and Behaviour
Acids, bases and salts : General properties, examples and uses, concept of pH scale, importance of pH in everyday life; preparation and uses of sodium hydroxide, Bleaching powder, Baking soda, washing soda and Plaster of Paris.
Chemical reactions : Chemical Equation, Types of chemical reactions : combination, decomposition, displacement, double displacement, precipitation, neutralization, oxidation and reduction in terms of gain and loss of oxygen and hydrogen.
Metals and non metals : General properties of Metals and Non-metals, reactivity series, Formation and properties of ionic compounds, Basic Metallurgical processes, corrosion and its prevention.
Carbon Compounds : Covalent bonding in carbon compounds. Versatile nature of carbon, Nomenclature of carbon compounds, Functional groups, difference between saturated hydrocarbons and unsaturated hydrocarbons, Ethanol and Ethanoic acid (only properties and uses), soaps and detergents.
Periodic classification of elements : Modern Periodic table, Gradation in Properties.
Theme : The world of the living (50 Periods)
Unit 2 : World of Living
Life Processes : "living" things; Basic concept of nutrition, respiration, transport and excretion in plants and animals.
Control and Co-ordination in animals and plants : Tropic movements in plants; Introduction to plant hormones; control and co-ordination in animals : voluntary, involuntary and reflex action, nervous system; chemical co-ordination : animal hormones.
Reproduction : Reproduction in animal and plants (asxual and sxual). Need for and methods of family planning. Safe sx vs HIV/AIDS. Child bearing and women's health.
Heridity and evolution : Heridity; Origin of life : brief introduction; Basic concepts of evolution.
Theme : How things work. (35 Periods)
Unit 3 : Effects of Current
Potential difference and electric current. Ohm's law; Resistance, Factors on which the resistance of a conductor depends. Series combination of resistors, parallel combination of resistors; Heating effect of Electric current; Electric Power, Inter relation between P, V, I and R.
Magnets : Magnetic field, field lines, field due to a current carrying wire, field due to current carrying coil or solenoid; Force on current carrying conductor, Fleming's left hand rule. Electro magnetic induction. Induced potential difference, Induced current. Fleming's Right Hand Rule, Direct current. Alternating current; frequency of AC. Advantage of AC over DC. Domestic electric circuits.
Theme : Natural Phenomena (20 Periods)
Unit 4 : Reflection of light at curved surfaces, Images formed by spherical mirrors, centre of curvature, principalaxis, principal focus, focal length. Mirror Formula (Derivation not required), Magnification. Refraction; laws of refraction, refractive index.Refraction of light by spherical lens, Image formed by spherical lenses, Lens formula (Derivation not required),Magnification. Power of a lens; Functioning of a lens in human eye, problems of vision and remedies, applications of
spherical mirrors and lenses.Refraction of light through a prism, dispersion of light, scattering of light, applications in daily life.
Theme : Natural Resources (20 Periods)
Unit 5 : Conservation of natural resources : Management of natural resources. Conservation and judicious use of natural resources. Forest and wild life, coal and petroleum conservation. Examples of People's participationfor conservation of natural resources.
The Regional environment : Big dams : advantages and limitations; alternatives if any. Water harvesting. Sustainability of natural resources.
Sources of energy : Different forms of energy, conventional and non-conventional sources of energy: fossil fuels, solar energy; biogas; wind, water and tidal energy; nuclear. Renewable versus non-renewable sources.
Our Environment : Eco-system, Environmental problems, their solutions. Biodegradable and non-biodegradable, substances ozone depletion.
PRACTICALS
LIST OF EXPERIMENTS
Marks : 40 (20 + 20 )
1. To find the pH of the following samples by using pH paper/universal indicator.
i) Dilute Hydrochloric acid
ii) Dilute NaOH solution
iii) Dilute Ethanoic acid solution
iv) Lemon juice
v) Water
vi) Dilute Sodium Bicarbonate Solution.
2. To study the properties of acids and bases HCl & NaOH by their reaction with
i) Litmus solution (Blue/Red)
ii) Zinc metal
iii) Solid Sodium Carbonate
3. To determine the focal length of 72
a) Concave mirror
b) Convex lens by obtaining the image of a distant object.
4. To trace the path of a ray of light passing through a rectangular glass slab for different angles of incidence. Measure the angle of incidence, angle of refraction, angle of emergence and interpret the result.
5. To study the dependence of current (I) on the potential difference (V) across a resistor and determine its resistance. Also plot a graph between V and I.
6. To determine the equivalent resistance of two resistors when connected in series.
7. To determine the equivalent resistance of two resistors when connected in parallel.
8. To prepare a temporary mount of a leaf peel to show stomata.
9. To show experimentally that light is necessary for photosynthesis.
10. To show experimentally that carbon dioxide is given out during respiration.
11. To study (a) binary fission in Amoeba and (b) budding in yeast with the help of prepared slides.
12. To determine the percentage of water absorbed by raisins.
13. To perform and observe the following reactions and classify them into:
i) Combination Reaction
ii) Decomposition Reaction
iii) Displacement Reaction
iv) Double Displacement Reaction
1. Action of water on quick lime.
2. Action of heat on Ferrous Sulphate crystals
3. Iron Nails kept in copper sulphate solution
4. Reaction between Sodium sulphate and Barium chloride solutions.
14. a) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions.
i) ZnSO4 (aq.)
ii) FeSO4 (aq.)
iii) CuSO4 (aq.)
iv) Al2 (SO4)3 (aq.)
b) Arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on the above result.
15. To study the following properties of acetic acid (ethanoic acid) :
73
i) odour
ii) solubility in wate
iii) effect on litmus
iv) reaction with sodium bicarbonate
SCHEME OF EVALUATION :
External Examination (to be conducted by the Board through multiple choice type written test) 20 Marks
School-based hands-on practical examination. 20 Marks
RECOMMENDED BOOKS :
Science - Textbook for class IX - NCERT Publication
Science - Textbook for class X - NCERT Publication
Assessment of Practical Skills in Science - Class IX - CBSE Publication
Assessment of Practical Skills in Science - Class X - CBSE Publication
CBSE Science Chap 1 - Chemical Reactions and Equations
Chapter Summary
- A complete chemical equation represents the reactants, products and their physical states symbolically.
- A chemical equation is balanced so that the numbers of atoms of each type involved in a chemical reaction are the same on the reactant and product sides of the equation. Equations must always be balanced.
- In a combination reaction two or more substances combine to form a new single substance.
- Decomposition reactions are opposite to combination reactions. In a decomposition reaction, a single substance decomposes to give two or more substances.
- Reactions in which heat is given out along with the products are called exothermic reactions.
- Reactions in which energy is absorbed are known as endothermic reactions.
- When an element displaces another element from its compound, a displacement reaction occurs.
- Two different atoms or groups of atoms (ions) are exchanged in double displacement reactions.
- Precipitation reactions produce insoluble salts.
- Reactions also involve the gain or loss of oxygen or hydrogen by substances.
- Oxidation is the gain of oxygen or loss of hydrogen. Reduction is the loss of oxygen or gain of hydrogen.
NCERT Book Solutions
NCERT Solutions - Chemical Reactions and Equations - Page 14 - Q1
1. Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s) → 2Pb(s) + CO2(g)
(a) Lead is getting reduced.
(b) Carbon dioxide is getting oxidised.
(c) Carbon is getting oxidised.
(d) Lead oxide is getting reduced.
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) all
(i) (a) and (b)
Chap 1 - Chemical Reactions and Equations - Page 6 - Q2
2. Write the balanced equation for the following chemical reactions.
(i) Hydrogen + Chlorine → Hydrogen chloride
(ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
(iii) Sodium + Water → Sodium hydroxide + Hydrogen
| 2 (i) | H2 + Cl2 -----------> 2HCl |
| 2 (ii) | 3BaCl2 + Al2(SO4)3 -------------> 3BaSO4 + 2AlCl3 |
| 2 (iii) | 2Na + 2H2O -----------------> 2NaOH + H2 |
Chap 1 - Chemical Reactions and Equations - Page 6 - Q3
3. Write a balanced chemical equation with state symbols for the following reactions.
(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
| 3 (i) | BaCl2 + Na2SO4 ---------------> BaSO4 + 2NaCl |
| 3 (iI) | NaOH + HCl -----------------> NaCl + H2O |
Chap 1 - Chemical Reactions and Equations - Page 6 - Q1
1. Why should a magnesium ribbon be cleaned before burning in air?
When Magnesium ribbon is stored, it reacts with oxygen to form a layer magnesium oxide . This layer of magnesium oxide is quite stable and prevents further reaction of magnesium with oxygen.And Hence a magnesium ribbon should be cleaned before burning in air.
NCERT Solutions - Chemical Reactions and Equations - Page 10 - Q1
1. A solution of a substance ‘X’ is used for white washing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.
| 1 (i) | The substance is calcium oxide ( Quick Lime) . Its Formula is CaO |
| 1 (ii) | CaO + H2O -----------> Ca(OH)2 |
NCERT Solutions - Chemical Reactions and Equations - Page 10 - Q2
2. Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
During electrolysis of water , hydrogen and oxygen gases are produced . Water (H2O) contains two parts hydrogen and one part oxygen.Since hydrogen goes to one test tube and oxygen goes to another, the amount of hydrogen gas in one of the test tubes is double of the amount of oxygen gas collected in the other tube.
NCERT Solutions - Chemical Reactions and Equations - Page 13 - Q1
1. Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
When an iron nail is placed in a copper sulphate solution, iron displaces copper from copper sulphate solution forming iron sulphate, which is green in colour. And hence the colour of copper sulphate solution change when an iron nail is dipped in it.
NCERT Solutions - Chemical Reactions and Equations - Page 13 - Q2
2. Give an example of a double displacement reaction other than the one given in Activity 1.10.
Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride is a example of a double displacement reaction.
NCERT Solutions - Chemical Reactions and Equations - Page 13 - Q3
3. Identify the substances that are oxidised and the substances that are reduced in the following reactions.
(i) 4Na(s) + O2(g) → 2Na2O(s)
(ii) CuO(s) + H2(g) → Cu(s) + H2O(l)
| 3 (i) | Sodium is oxidised to Sodium Oxide and Oxygen is reduced. |
| 3 (ii) | CuO is reduced to Cu and Hydrogen is oxidised to H2O |
NCERT Solutions - Chemical Reactions and Equations - Page 14 - Q2
2. Fe2O3 + 2Al → Al2O3 + 2Fe
The above reaction is an example of a
(a) combination reaction.
(b) double displacement reaction.
(c) decomposition reaction.
(d) displacement reaction.
(d) displacement reaction.
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q10
Human Beings need energy to stay alive. We get this energy from the food we eat. During digestion, food is broken down into simpler substances. For example, rice, potatoes and bread contain carbohydrates. These carbohydrates are broken down to form glucose. This glucose combines with oxygen in the cells of our body and provides energy. The special name of this reaction is respiration. Energy is released in the process and hence exothermic reaction.
C6H12O6(aq) + 6O2(aq) → 6CO2(aq) + 6H2O(l) + energy
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q11
11. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
In a decomposition reaction, a single substance decomposes to give two or more substances. Whereas In a combination reaction two or more substances combine to form a new single substance. And hence ,Decomposition reactions are opposite to combination reactions.
Decomposition Reaction : AB + Energy ----------> A + B
CaCO3(s) -----Heat----------- > CaO(s) + CO2(g)
Composition Reaction : A + B --------------> AB + Energy
Example : Burning of coal
C(s) + O2(g) → CO2(g)
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q3
3. What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer.
(a) Hydrogen gas and iron chloride are produced.
(b) Chlorine gas and iron hydroxide are produced.
(c) No reaction takes place.
(d) Iron salt and water are produced.
(a) Hydrogen gas and iron chloride are produced.
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q4
4. What is a balanced chemical equation? Why should chemical equations be balanced?
A chemical equation is balanced when the numbers of atoms of each type involved in a chemical reaction are same on both the reactant and product sides of the equation.
As perthe law of conservation of mass that mass can neither be created nor destroyed in a chemical reaction. That is, the
total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants. And Hence chemical equations must always be balanced.
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q5
5. Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
| 5 (a) | 3H2 + N2 --------------> 2NH3 |
| 5 (b) | 2H2S + 302 ----------------------> 2H2O + 2SO2 |
| 5 (c) | 3BaCl2 + Al2(SO4)3 ---------------------> 2AlCl3 + 3BaSO4 |
| 5 (d) | 2K + 2H2O --------> 2KOH + H2 |
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q6
6. Balance the following chemical equations.
(a) HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O
(b) NaOH + H2SO4 → Na2SO4 + H2O
(c) NaCl + AgNO3 → AgCl + NaNO3
(d) BaCl2 + H2SO4 → BaSO4 + HCl
(a) 2HNO3 + Ca(OH)2 → Ca(NO3)2 + 2H2O
(b) 2NaOH + H2SO4 → Na2SO4 + 2H2O
(c) NaCl + AgNO3 → AgCl + NaNO3
(d) BaCl2 + H2SO4 → BaSO4 + 2HCl
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q7
7. Write the balanced chemical equations for the following reactions.
(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
(b) Zinc + Silver nitrate → Zinc nitrate + Silver
(c) Aluminium + Copper chloride → Aluminium chloride + Copper
(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride
| 7 (a) | Ca(OH)2 + CO2 ------------> CaCO3 + H2O |
| 7 (b) | Zn + 2AgNO3 -------------> Zn(NO3)2 + 2Ag |
| 7 (c) | 2Al + 3CuCl2 ----------> 2AlCl3 + 3Cu |
| 7 (d) | BaCl2 + K2SO4 ---------> BaSO4 + 2KCl |
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q8
8. Write the balanced chemical equation for the following and identify the type of reaction in each case.
(a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)
(b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)
(c) Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)
(d) Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq) + Hydrogen(g)
| 8 (a) | 2KBr + BaI2 --------> 2KI + BaBr2 , Double Displacement Reaction |
| 8 (b) | ZnCO3 -------> ZnO + CO2 , Decomposition Reaction |
| 8 (c) | H2 + Cl2 ------------------> 2HCl , Composition Reaction |
| 8 (d) | Mg + 2HCl ----------> MgCl2 + H2 , Displacement Reaction |
NCERT Solutions - Chemical Reactions and Equations - Page 15 - Q9
9. What does one mean by exothermic and endothermic reactions? Give examples.
Reactions in which heat is released along with the formation of products are called exothermic chemical reactions.
Examples of exothermic reactions are –
Burning of natural gas
CH4(g) + 2O2 (g) → CO2 (g) + 2H2O (g)
Reactions in which energy is absorbed are known as endothermic reactions.
Examples of endothermic reactions are –
2AgBr(s) -----------Sunlight -----> 2Ag(s) + Br2(g)
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q12
12. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
| Heat | CaCO3(s) -----------Heat→ CaO(s) + CO2(g) |
| Light | 2AgBr(s) -----------Sunlight→2Ag(s) + Br2(g) |
| Electricity | 2Al2O3 --------------> 4Al + 3O2 |
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q13
13. What is the difference between displacement and double displacement reactions? Write equations for these reactions.
When an element displaces another element from its compound, a displacement reaction occurs. Whereas two different atoms or groups of atoms (ions) are exchanged in double displacement reactions.
Displacement Reaction
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
Pb(s) + CuCl2(aq) → PbCl2(aq) + Cu(s)
Double Displacement Reaction
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q14
14. In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
AgNO3 + Cu ----------> Cu(NO3)2 + 2Ag
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q15
15. What do you mean by a precipitation reaction? Explain by giving examples.
Any reaction that produces a precipitate can be called a precipitation reaction.Precipitation reactions produce insoluble salts.
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
The white precipitate of BaSO4 is formed by the reaction of SO42– and Ba2+. The other product formed is sodium chloride
which remains in the solution.
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q16
16. Explain the following in terms of gain or loss of oxygen with two examples each.
(a) Oxidation
(b) Reduction
(a) Oxidation : Oxidation is the gain of oxygen or loss of hydrogen.
(b)Reduction : Reduction is the loss of oxygen or gain of hydrogen.
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q17
17. A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
The element ‘X’ is Copper and the black coloured compound is Copper Oxide (CuO) .The Chemical reaction is
2Cu + O2 ---------------Heat→2CuO
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q18
18. Why do we apply paint on iron articles?
Iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process
is commonly known as rusting of iron (Corrosion) . Corrosion causes damage to car bodies, bridges, iron railings, ships
and to all objects made of metals, specially those of iron. Corrosion of iron is a serious problem. Every year an enormous amount of money is spent to replace damaged iron. And hence to avoid rusting of iron , paint is applied on iron articles.
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q19
19. Oil and fat containing food items are flushed with nitrogen. Why?
When fats and oils are oxidised, they become rancid and their smell and taste change. Usually substances which prevent oxidation (antioxidants) are added to foods containing fats and oil. Keeping food in air tight containers helps to slow down oxidation. Nitrogen is an inert gas and act as an antioxidant to prevent rancidity of Oil and fat containing food items.
Chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidised
NCERT Solutions - Chemical Reactions and Equations - Page 16 - Q20
20. Explain the following terms with one example each.
(a) Corrosion
(b) Rancidity
(a) Corrosion: When a metal is attacked by substancesa round it such as moisture, acids, etc., it is said to corrode and this
process is called corrosion.
The black coating on silver and the green coating on copper are other examples of corrosion.
(b) Rancidity : When fats and oils are oxidised and their smell and taste change. This process is known as Rancidity
Examples : Butter when kept in open for long time , tastes and smell bad.
CBSE Science Chap 2 - Acids, Bases and Salts
Chapter Summary
- Acid-base indicators are dyes or mixtures of dyes which are used to indicate the presence of acids and bases.
- Acidic nature of a substance is due to the formation of H+(aq) ions in solution. Formation of OH–(aq) ions in solution is responsible for the basic nature of a substance.
- When an acid reacts with a metal, hydrogen gas is evolved and a corresponding salt is formed.
- When a base reacts with a metal, along with the evolution of hydrogen gas a salt is formed which has a negative ion composed of the metal and oxygen.
- When an acid reacts with a metal carbonate or metal hydrogencarbonate, it gives the corresponding salt, carbon dioxide gas and water.
- Acidic and basic solutions in water conduct electricity because they produce hydrogen and hydroxide ions respectively.
- The strength of an acid or an alkali can be tested by using a scale called the pH scale (0-14) which gives the measure of hydrogen ion concentration in a solution.
- A neutral solution has a pH of exactly 7, while an acisolution has a pH less than 7 and a basic solution a pH more than 7.
- Living beings carry out their metabolic activities within an optimal pH range.
- Mixing concentrated acids or bases with water is a highly exothermic process.
- Acids and bases neutralise each other to form corresponding salts and water.
- Water of crystallisation is the fixed number of water molecules chemically attached to each formula unit of a salt in its crystalline form.
- Salts have various uses in everyday life and in industries.
NCERT Book Solutions
NCERT Solutions - Acids , Bases and Salts - Page 18 - Q1
1. You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Bases change the colour of the red litmus to blue.
NCERT Solutions - Acids , Bases and Salts - Page 22 - Q1
1. Why should curd and sour substances not be kept in brass and copper vessels?
NCERT Solutions - Acids , Bases and Salts - Page 22 - Q2
2. Which gas is usually liberated when an acid reacts with a metal?
Illustrate with an example. How will you test for the presence of this gas?
NCERT Solutions - Acids , Bases and Salts - Page 22 - Q3
3. Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds
formed is calcium chloride.
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q1
1. Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q2
2. Why does an aqueous solution of an acid conduct electricity?
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q3
3. Why does dry HCl gas not change the colour of the dry litmus paper?
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q4
4. While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q5
5. How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted?
NCERT Solutions - Acids , Bases and Salts - Page 25 - Q6
6. How is the concentration of hydroxide ions (OH–) affected when excess base is dissolved in a solution of sodium hydroxide?
NCERT Solutions - Acids , Bases and Salts - Page 33 - Q1
1. What is the common name of the compound CaOCl2?
NCERT Solutions - Acids , Bases and Salts - Page 33 - Q2
2. Name the substance which on treatment with chlorine yields bleaching powder.
NCERT Solutions - Acids , Bases and Salts - Page 33 - Q3
3. Name the sodium compound which is used for softening hard water.
NCERT Solutions - Acids , Bases and Salts - Page 33 - Q5
5. Write an equation to show the reaction between Plaster of Paris and water.
NCERT Solutions - Acids , Bases and Salts - Page 33- Q4
4. What will happen if a solution of sodium hydrocarbonate is heated?
Give the equation of the reaction involved.
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q1
1. A solution turns red litmus blue, its pH is likely to be
(a) 1 (b) 4 (c) 5 (d) 10
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q2
2. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky.
The solution contains
(a) NaCl (b) HCl (c) LiCl (d) KCl
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q3
3. 10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount HCl solution (the same solution as before) required to neutralise it will be
(a) 4 mL (b) 8 mL (c) 12 mL (d) 16 mL
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q5
5. Write word equations and then balanced equations for the reaction taking place when –
(a) dilute sulphuric acid reacts with zinc granules.
(b) dilute hydrochloric acid reacts with magnesium ribbon.
(c) dilute sulphuric acid reacts with aluminium powder.
(d) dilute hydrochloric acid reacts with iron filings.
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q6
6. Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it.
NCERT Solutions - Acids , Bases and Salts - Page 34 - Q7
7. Why does distilled water not conduct electricity, whereas rain water does?
NCERT Solutions - Acids , Bases and Salts - Page 34- Q4
4. Which one of the following types of medicines is used for treating indigestion?
(a) Antibiotic
(b) Analgesic
(c) Antacid
(d) Antiseptic
NCERT Solutions - Acids , Bases and Salts - Page 35- Q8
8. Why do acids not show acidic behaviour in the absence of water?
NCERT Solutions - Acids , Bases and Salts - Page 35- Q9
9. Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is
(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.
NCERT Solutions - Acids , Bases and Salts - Page 35 - Q10
10. Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. In which test tube will the fizzing occur more vigorously and why?
NCERT Solutions - Acids , Bases and Salts - Page 35 - Q11
11. Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.
NCERT Solutions - Acids , Bases and Salts - Page 35 - Q12
12. A milkman adds a very small amount of baking soda to fresh milk.
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?
NCERT Solutions - Acids , Bases and Salts - Page 35 - Q13
13. Plaster of Paris should be stored in a moisture-proof container. Explain why?
NCERT Solutions - Acids , Bases and Salts - Page 35 - Q14
14. What is a neutralisation reaction? Give two examples.
CBSE Science Chap 3 - Metals and Non-metals
Chapter Summary
- Elements can be classified as metals and non-metals.
- Metals are lustrous, malleable, ductile and are good conductors of heat and
- electricity. They are solids at room temperature, except mercury which is a liquid.
- Metals can form positive ions by losing electrons to non-metals.
- Metals combine with oxygen to form basic oxides. Aluminium oxide and zinc oxide show the properties of both basic as well as acidic oxides. These oxides are known as amphoteric oxides.
- Different metals have different reactivities with water and dilute acids.
- A list of common metals arranged in order of their decreasing reactivity is known as an activity series.
- Metals above hydrogen in the Activity series can displace hydrogen from dilute acids. A more reactive metal displaces a less reactive metal from its salt solution.
- Metals occur in nature as free elements or in the form of their compounds.
- The extraction of metals from their ores and then refining them for use is known as metallurgy.
- An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal.
- The surface of some metals, such as iron, is corroded when they are exposed to moist air for a long period of time. This phenomenon is known as corrosion.
- Non-metals have properties opposite to that of metals. They are neither malleable nor ductile. They are bad conductors of heat and electricity, except for graphite, which conducts electricity.
- Non-metals form negatively charged ions by gaining electrons when reacting with metals.
- Non-metals form oxides which are either acidic or neutral.
- Non-metals do not displace hydrogen from dilute acids. They react with hydrogen to form hydrides.
NCERT Book Solutions
CBSE Science Chap 3 - Metals and Non-metals - P40 - Q1
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
CBSE Science Chap 3 - Metals and Non-metals - P40 - Q2
Explain the meanings of malleable and ductile.
CBSE Science Chap 3 - Metals and Non-metals - P46 - Q1
Why is sodium kept immersed in kerosene oil?
CBSE Science Chap 3 - Metals and Non-metals - P46 - Q2
Write equations for the reactions of
(i) iron with steam
(ii) calcium and potassium with water
CBSE Science Chap 3 - Metals and Non-metals - P46 - Q3
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal Iron (II) sulphate Cooper (II) sulphate Zinc sulphate Silver nitrate
A. No reaction Displacement
B. Displacement No reaction
C. No reaction No reaction No reaction Displacement
D. No reaction No reaction No reaction No reaction
Use the Table above to answer the following questions about metals A, B, C and D.
(i) Which is the most reactive metal?
(ii) What would you observe if B is added to a solution of copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
CBSE Science Chap 3 - Metals and Non-metals - P46 - Q4
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
CBSE Science Chap 3 - Metals and Non-metals - P46 - Q5
What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place.
CBSE Science Chap 3 - Metals and Non-metals - P49 - Q1
(i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by the transfer of electrons.
(iii) What are the ions present in these compounds?
CBSE Science Chap 3 - Metals and Non-metals - P49 - Q2
Why do ionic compounds have high melting points?
CBSE Science Chap 3 - Metals and Non-metals - P53 - Q1
Define the following terms.
(i) Mineral (ii) Ore (iii) Gangue
CBSE Science Chap 3 - Metals and Non-metals - P53 - Q1
Defin the following terms.
(i) Mineral (ii) Ore (iii) Gangue
CBSE Science Chap 3 - Metals and Non-metals - P53 - Q2
Name two metals which are found in nature in the free state.
CBSE Science Chap 3 - Metals and Non-metals - P53 - Q3
What chemical process is used for obtaining a metal from its oxide?
CBSE Science Chap 3 - Metals and Non-metals - P55 - Q1
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
|
Metal |
Zinc |
Magnesium |
Copper |
|
Zinc oxide |
- |
- |
- |
|
Magnesium oxide |
- |
- |
- |
|
Copper oxide |
- |
- |
- |
In which cases will you find displacement reactions taking place?
CBSE Science Chap 3 - Metals and Non-metals - P55 - Q2
Which metals do not corrode easily?
CBSE Science Chap 3 - Metals and Non-metals - P55 - Q3
What are alloys?
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q1
Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminium metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal.
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q2
Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) all of the above.
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q3
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) calcium
(b) carbon
(c) silicon
(d) iron
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q4
Food cans are coated with tin and not with zinc because
(a) zinc is costlier than tin.
(b) zinc has a higher melting point than tin.
(c) zinc is more reactive than tin.
(d) zinc is less reactive than tin.
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q5
You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q6
What are amphoteric oxides? Give two examples of amphoteric oxides.
CBSE Science Chap 3 - Metals and Non-metals - P56 - Q7
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q8
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q9
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
(Fig)
(a) What will be the action of gas on
(i) dry litmus paper?
(ii) moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q10
State two ways to prevent the rusting of iron.
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q11
What type of oxides is formed when non-metals combine with oxygen?
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q12
Give reasons
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
CBSE Science Chap 3 - Metals and Non-metals - P57 - Q13
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
CBSE Science Chap 4 - Carbon and its Compounds
Chapter Summary
- Carbon is a versatile element that forms the basis for all living organisms and manyof the things we use.
- This large variety of compounds is formed by carbon because of its tetravalency and the property of catenation that it exhibits.
- Covalent bonds are formed by the sharing of electrons between two atoms so that both can achieve a completely filled outermost shell.
- Carbon forms covalent bonds with itself and other elements such as hydrogen ,oxygen, sulphur, nitrogen and chlorine.
- Carbon also forms compounds containing double and triple bonds between carbon atoms. These carbon chains may be in the form of straight chains, branched chains or rings.
- The ability of carbon to form chains gives rise to a homologous series of compounds which the same functional group is attached to carbon chains of different lengths.
- The functional groups such as alcohols, aldehydes, ketones and carboxylic acids bestow characteristic properties to the carbon compounds that contain them.
- Carbon and its compounds are some of our major sources of fuels.
- Ethanol and ethanoic acid are carbon compounds of importance in our daily lives.
- The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule and this helps to emulsify the oily dirt and hence its removal.
NCERT Book Solutions
CBSE Science Chap 4 - Carbon and its Compounds - P61 - Q1
What would be the electron dot structure of carbon dioxide which has the formula CO2?
Electron dot structure of CO2 is
(IMAGES)
CBSE Science Chap 4 - Carbon and its Compounds - P61 - Q2
What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? (Hint − the eight atoms of sulphur are joined together in the form of a ring.)
Electron dot structure of a sulphur molecule
(IMAGES)
CBSE Science Chap 4 - Carbon and its Compounds - P68 - Q1
How many structural isomers can you draw for pentane?
CBSE Science Chap 4 - Carbon and its Compounds - P68 - Q2
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
The two features of carbon that give rise to a large number of compounds are as follows -
(i) Catenation − Carbon has the unique ability to form bonds with other atoms of carbon.
(ii) Tetravalency − With the valency of four, carbon is capable of bonding with four other atoms of carbon or atoms of some other mono-valent element.
CBSE Science Chap 4 - Carbon and its Compounds - P68 - Q3
What will be the formula and electron dot structure of cyclopentane?
CBSE Science Chap 4 - Carbon and its Compounds - P69 - Q4
Draw the structures for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal
*Are structural isomers possible for bromopentane?
CBSE Science Chap 4 - Carbon and its Compounds - P69 - Q5
How would you name the following compounds?
(i) (IMAGES)
(ii) (IMAGES)
(iiii)(IMAGES)
(i) Bromoethane
(ii) Methanal (formaldehyde)
(iii) Hexyne
CBSE Science Chap 4 - Carbon and its Compounds - P71 - Q1
Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
CBSE Science Chap 4 - Carbon and its Compounds - P71 - Q2
A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?
(IMAGES)
When ethyne is burnt in air, it gives a sooty flame. The reason is incomplete combustion caused by limited supply of air. But when ethyne is burnt with oxygen, it gives a clean flame with temperature 3000°C due to complete combustion. This oxy-acetylene flame is used for welding and It is not possible to attain such a high temperature without mixing only oxygen. And for this reason, a mixture of ethyne and air is not used for welding.
CBSE Science Chap 4 - Carbon and its Compounds - P74 - Q1
How would you distinguish experimentally between an alcohol and a carboxylic acid?
Acid reacts with carbonate and hydrogen carbonate to evolve CO2 gas that turns lime water milky. Whereas alcohols do not react with carbonates and hydrogen carbonates. So we can distinguish between an alcohol and a carboxylic acid based on their reaction with carbonates and hydrogen carbonates.
CBSE Science Chap 4 - Carbon and its Compounds - P74 - Q2
What are oxidising agents?
Some substancesare capable of adding oxygen to others. These are known as oxidising agents.The examples of oxidising agents are alkaline potassium permanganate and acidified potassium dichromate
CBSE Science Chap 4 - Carbon and its Compounds - P76 - Q1
Would you be able to check if water is hard by using a detergent?
Detergents are ammonium or sulphonate salts of long chain carboxylic acids. The charged ends of these compounds do not form insoluble precipitates with the calcium and magnesium ions in hard water as well. Detergents do not react with calcium and magnesium ions present in hard water to form scum like soap does. They give a good amount of lather irrespective of whether the water is hard or soft. This means that detergents can be used in both soft and hard water. Hence, it cannot be used to check whether the water is hard or not.
CBSE Science Chap 4 - Carbon and its Compounds - P76 - Q2
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
A soap molecule has two parts known as hydrophobic and hydrophilic. With the help of these, it attaches to the grease or dirt particle and forms a cluster called micelle. The micelles stay in solution as a colloid and will not come together to precipitate because of ion-ion repulsion.To remove these micelles (entrapping the dirt), it is necessary to agitate clothes.
CBSE Science Chap 4 - Carbon and its Compounds - P77 - Q1
Ethane, with the molecular formula C2H6 has
(a) 6 covalent bonds.
(b) 7 covalent bonds.
(c) 8 covalent bonds.
(d) 9 covalent bonds.
(b) Ethane has 7 covalent bonds.
CBSE Science Chap 4 - Carbon and its Compounds - P77 - Q2
Butanone is a four-carbon compound with the functional group
(a) carboxylic acid.
(b) aldehyde.
(c) ketone.
(d) alcohol.
(c) The functional group of butanone is ketone.
CBSE Science Chap 4 - Carbon and its Compounds - P77 - Q3
While cooking, if the bottom of the vessel is getting blackened on the outside, it means that
(a) the food is not cooked completely.
(b) the fuel is not burning completely.
(c) the fuel is wet.
(d) the fuel is burning completely.
(b) the fuel is not burning completely
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q4
Explain the nature of the covalent bond using the bond formation in CH3Cl.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q5
Draw the electron dot structures for
(a) ethanoic acid.
(b) H2S.
(c) propanone.
(d) F2.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q6
What is a homologous series? Explain with an example.
A homologous series is a series of carbon compounds that have different numbers of carbon atoms but contain the same functional group.
For example, methane, ethane, propane, butane, etc. are all part of the alkane homologous series. The general formula of this series is CnH2n+2.
Methane CH4
Ethane CH3CH3
Propane CH3CH2CH3
Butane CH3¬CH2CH2CH3
It can be noticed that there is a difference of −CH2 unit between each successive compound.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q7
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
• Ethanol is a liquid at room temperature with a pleasant odour while ethanoic acid has vinegar-like smell. The melting point of ethanoic acid is 17°C. This is below room temperature and hence, it freezes during winters.
• Ethanoic acid reacts with metal carbonates and metal hydrogencarbonates to form salt, water, and carbon dioxide gas while ethanol does not react with them.
(IMAGES)
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q8
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
A soap is a sodium or potassium salt of long chain fatty acids. It has one polar end and one non-polar end. The polar end is hydrophilic in nature i.e., this end is attracted towards water. The non-polar end is hydrophobic but lipophilic, i.e., it is attracted towards hydrocarbons. When soap is added to water, soap molecules arrange themselves in a cluster to keep the non-polar portion out of water such that the non-polar ends are in the interior of the cluster and the polar ends are on the surface of the cluster. Since the dirt present on clothes is organic in nature and insoluble in water, the hydrophobic ends of the clusters attach themselves to the dirt. This cluster formation in which the dirt is entrapped is the micelle.
(IMAGES)
Micelle formation does not occur in alcohol because the alkyl chain of soap becomes soluble in alcohol.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q9
Why are carbon and its compounds used as fuels for most applications?
Most of the carbon compounds give a lot of heat and light when burnt in air. Saturated hydrocarbons burn with a clean flame and no smoke is produced. The carbon compounds, used as a fuel, have high calorific values. Therefore, carbon and its compounds are used as fuels for most applications.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q10
Explain the formation of scum when hard water is treated with soap.
Soap does not work properly when the water is hard. A soap is a sodium or potassium salt of long chain fatty acids. Hard water contains salts of calcium and magnesium. When soap is added to hard water, calcium and magnesium ions present in water displace sodium or potassium ions from the soap molecules forming an insoluble substance called scum. A lot of soap is wasted in the process.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q11
What change will you observe if you test soap with litmus paper (red and blue)?
Since soap is basic in nature, it will turn red litmus blue. However, the colour of blue litmus will remain blue.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q12
What is hydrogenation? What is its industrial application?
Hydrogenation is the process of addition of hydrogen. Unsaturated hydrocarbons are added with hydrogen in the presence of palladium and nickel catalysts to give saturated hydrocarbons.
(IMAGES)
This reaction is applied in the hydrogenation of vegetables oils, which contain long chains of unsaturated carbons.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q13
Which of the following hydrocarbons undergo addition reactions:
C2H6, C3H8, C3H6, C2H2 and CH4.
Unsaturated hydrocarbons undergo addition reactions. Being unsaturated hydrocarbons, C3H6 and C2H2 undergo addition reactions.
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q14
Give a test that can be used to differentiate chemically between butter and cooking oil.
Butter contains saturated fats. Therefore, it cannot be hydrogenated. On the other hand, oil has unsaturated fats. That is why it can be hydrogenated to saturated fats (solids).
CBSE Science Chap 4 - Carbon and its Compounds - P78 - Q15
Explain the mechanism of the cleaning action of soaps.
Cleansing action of soaps:
The dirt present on clothes is organic in nature and insoluble in water. Therefore, it cannot be removed by only washing with water. When soap is dissolved in water, its hydrophobic ends attach themselves to the dirt and remove it from the cloth. Then, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster. These micelles remain suspended in the water. Hence, the dust particles are easily rinsed away by water.
(IMAGES)
Chap 5 - Periodic Classification of Elements
Chap 5 - Periodic Classification of Elements - P81 - Q1
Did Dobereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
Only one triad of Dobereiner’s triads exists in the columns of Newlands’ octaves. The triad formed by the elements Li, Na, and K of Dobereiner’s triads also occurred in the columns of Newlands’ octaves.
Dobereiner’s triads
|
Li |
Ca |
Cl |
|
Na |
Sr |
Br |
|
K |
Ba |
I |
Newlands’ octaves
|
H |
Li |
Be |
B |
C |
N |
O |
|
F |
Na |
Mg |
Al |
Si |
P |
S |
|
Cl |
K |
Ca |
Cr |
Ti |
Mn |
Fe |
|
Co and Ni |
Cu |
Zn |
Y |
In |
As |
Se |
|
Br |
Rb |
Sr |
Ce and La |
Zr |
− |
− |
Chap 5 - Periodic Classification of Elements - P81 - Q2
What were the limitations of Dobereiner’s classification?
Limitation of Dobereiner’s classification:
All known elements could not be classified into groups of triads on the basis of their properties.
Chap 5 - Periodic Classification of Elements - P81 - Q3
What were the limitations of Newlands’ Law of Octaves?
Limitations of Newlands’ law of octaves:
(i) It was not applicable throughout the arrangements. It was applicable up to calcium only. The properties of the elements listed after calcium showed no resemblance to the properties of the elements above them.
(ii) Those elements that were discovered after Newlands’ octaves did not follow the law of octaves.
(iii) The position of cobalt and nickel in the group of the elements (F, Cl) of different properties could not be explained.
(iv) Placing of iron far away from cobalt and nickel, which have similar properties as iron, could also not be explained.
Chap 5 - Periodic Classification of Elements - P85 - Q1
Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, Al, Si, Ba.
K is in group 1. Therefore, the oxide will be K2O.
C is in group 4. Therefore, the oxide will be CO2.
Al is in group 3. Therefore, the oxide will be Al2O3.
Si is in group 4. Therefore, the oxide will be SiO2.
Ba is in group 2. Therefore, the oxide will be BaO.
Chap 5 - Periodic Classification of Elements - P85 - Q2
Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)
Scandium and germanium
Chap 5 - Periodic Classification of Elements - P85 - Q3
What were the criteria used by Mendeleev in creating his Periodic Table?
Mendeleev’s periodic table was based on the observation that the properties of elements are a periodic function of their atomic masses. This means that if elements are arranged in the increasing order of their atomic masses, then their properties get repeated after regular intervals.
Chap 5 - Periodic Classification of Elements - P85 - Q4
Why do you think the noble gases are placed in a separate group?
Noble gases are inert elements. Their properties are different from the all other elements. Therefore, the noble gases are placed in a separate group.
Chap 5 - Periodic Classification of Elements - P90 - Q1
How could the Modern Periodic Table remove various anomalies of Mendeleev’s Periodic Table?
Mendeleev was unable to give fixed position to hydrogen and isotopes in the periodic table. In Mendeleev’s periodic table, the increasing manner of atomic mass of the elements is not always regular from one to its next. It was believed that a more fundamental property than atomic mass could explain periodic properties in a better manner.
It was Henry Moseley who demonstrated that atomic number of an element could explain periodic properties in a better way than atomic mass of an element and arranged the elements in increasing order of their atomic numbers. Then it was found that the various anomalies of Mendeleev’s periodic table were removed by the modern periodic table.
Chap 5 - Periodic Classification of Elements - P90 - Q2
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
Calcium (Ca) and strontium (Sr) are expected to show chemical reactions similar to magnesium (Mg). This is because the number of valence electrons (2) is same in all these three elements. And since chemical properties are due to valence electrons, they show same chemical reactions.
Chap 5 - Periodic Classification of Elements - P90 - Q3
Name
(a) three elements that have a single electron in their outermost shells.
(b) two elements that have two electrons in their outermost shells.
(c) three elements with filled outermost shells.
(a) Lithium (Li), sodium (Na), and potassium (K) have a single electron in their outermost shells.
(b) Magnesium (Mg) and calcium (Ca) have two electrons in their outermost shells.
(c) Neon (Ne), argon (Ar), and xenon (Xe) have filled outermost shells.
Chap 5 - Periodic Classification of Elements - P90 - Q4
(a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?
(b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?
(a) Yes. The atoms of all the three elements lithium, sodium, and potassium have one electron in their outermost shells.
(b) Both helium (He) and neon (Ne) have filled outermost shells. Helium has a duplet in its K shell, while neon has an octet in its L shell.
Chap 5 - Periodic Classification of Elements - P90 - Q5
In the Modern Periodic Table, which are the metals among the first ten elements?
Among the first ten elements, lithium (Li) and beryllium (Be) are metals.
Chap 5 - Periodic Classification of Elements - P90 - Q6
By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?
Since Be lies to the extreme left hand side of the periodic table, Be is the most metallic among the given elements.
Chap 5 - Periodic Classification of Elements - P91 - Q1
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
(c) The atoms lose their electrons more easily.
(On moving from left to right across the periods of the periodic table, the non-metallic character increases. Hence, the tendency to lose electrons decreases.)
Chap 5 - Periodic Classification of Elements - P91 - Q2
Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
(a) Na (b) Mg (c) Al (d) Si
(b) X would most likely be in the same group of the Periodic Table as magnesium (Mg).
Chap 5 - Periodic Classification of Elements - P91 - Q3
Which element has
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?
(a) Neon has two shells, both of which are completely filled with electrons (2 electrons in K shell and 8 electrons in L shell).
(b) Magnesium has the electronic configuration 2, 8, 2.
(c) Silicon has a total of three shells, with four electrons in its valence shell (2 electrons in K shell, 8 electrons in L shell and 4 electrons in M shell).
(d) Boron has a total of two shells, with three electrons in its valence shell (2 electrons in K shell and 3 electrons in L shell).
(e) Carbon has twice as many electrons in its second shell as in its first shell (2 electrons in K shell and 4 electrons in L shell).
Chap 5 - Periodic Classification of Elements - P91 - Q4
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
(a) All the elements in the same column as boron have the same number of valence electrons (3). Hence, they all have valency equal to 3.
(b) All the elements in the same column as fluorine have the same number of valence electrons (7). Hence, they all have valency equal to 1.
Chap 5 - Periodic Classification of Elements - P91 - Q5
An atom has electronic configuration 2, 8, 7.
(a) What is the atomic number of this element?
(b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)
N(7) F(9) P(15) Ar(18)
(a) The atomic number of this element is 17.
(b) It would be chemically similar to F(9) with configuration as 2, 7.
Chap 5 - Periodic Classification of Elements - P92 - Q6
The position of three elements A, B and C in the Periodic Table are shown below −
|
Group 16 |
Group 17 |
|
− |
− |
|
− |
A |
|
− |
− |
|
B |
C |
(a) State whether A is a metal or non-metal.
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?
(d) Which type of ion, cation or anion, will be formed by element A?
(a) A is a non-metal.
(b) C is less reactive than A, as reactivity decreases down the group in halogens.
(c) C will be smaller in size than B as moving across a period, the nuclear charge increases and therefore, electrons come closer to the nucleus.
(d) A will form an anion as it accepts an electron to complete its octet.
Chap 5 - Periodic Classification of Elements - P92 - Q7
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
|
Element |
K L M |
|
Nitrogen Phosphorus |
2 5 2 8 5 |
Nitrogen is more electronegative than phosphorus. On moving down a group, the number of shell increases. Therefore, the valence electrons move away from the nucleus and the effective nuclear charge decreases. This causes the decrease in the tendency to attract electron and hence electronegativity decreases.
Chap 5 - Periodic Classification of Elements - P92 - Q8
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
In the modern periodic table, atoms with similar electronic configurations are placed in the same column. In a group, the number of valence electrons remains the same.
Elements across a period show an increase in the number of valence electrons.
Chap 5 - Periodic Classification of Elements - P92 - Q9
In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21, and 38. Which of these have physical and chemical properties resembling calcium?
The element with atomic number 12 has same chemical properties as that of calcium. This is because both of them have same number of valence electrons (2).
Chap 5 - Periodic Classification of Elements - P92 - Q10
Compare and contrast the arrangement of elements in Mendeleev’s periodic Table and the Modern Periodic Table.
|
|
Mendeleev’s periodic table |
|
Modern periodic table |
|
1. |
Elements are arranged in the increasing order of their atomic masses. |
1. |
Elements are arranged in the increasing order of their atomic numbers. |
|
2. |
There are a total of 7 groups (columns) and 6 periods (rows). |
2. |
There are a total of 18 groups (columns) and 7 periods (rows). |
|
3. |
Elements having similar properties were placed directly under one another. |
3. |
Elements having the same valence shell are present in the same period while elements having the same number of valence electrons are present in the same group. |
|
4. |
The position of hydrogen could not be explained. |
4. |
Hydrogen is placed above alkali metals. |
|
5. |
No distinguishing positions for metals and non-metals. |
5. |
Metals are present at the left hand side of the periodic table whereas non-metals are present at the right hand side. |
Chap 6 - Life Processes
Chap 6 - Life Processes - P95 - Q1
1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
In multi-cellular organisms, all the cells may not be in direct contact with the surrounding environment. Thus, simple diffusion will not meet the requirements of all the cells of multicellular organisms like humans.
Chap 6 - Life Processes - P95 - Q2
2. What criteria do we use to decide whether something is alive?
We tend to think of some sort of movement, either growth-related or not, as common evidence for being alive.But a plant that is not visibly growing is still alive, and some animals can breathe without visible movement. Thus Movements over very small scales will be invisible to the naked eye – movements of molecules, for example. Presense of this molecular level movements determines whether the organism is alive or not.
Chap 6 - Life Processes - P95 - Q3
3. What are outside raw materials used for by an organism?
Food and Oxygen are outside raw materials used for by an organism.
Chap 6 - Life Processes - P95 - Q4
4. What processes would you consider essential for maintaining life?
Life processes like respiration,nutrition, transportation, excretion are considered as essential for maintaining life.
Chap 6 - Life Processes - P101 - Q1
1. What are the differences between autotrophic nutrition and heterotrophic nutrition?
|
|
Autotrophic nutrition |
|
Heterotrophic nutrition |
|
(i) |
Food is synthesised from simple inorganic raw materials such as CO2 and water. |
(i) |
Food is obtained directly or indirectly from autotrophs. This food is broken down with the help of enzymes. |
|
(ii) |
Presence of green pigment (chlorophyll) is necessary. |
(ii) |
No pigment is required in this type of nutrition. |
|
(iii) |
Food is generally prepared during day time. |
(iii) |
Food can be prepared at all times. |
|
(iv) |
All green plants and some bacteria have this type of nutrition. |
(iv) |
All animals and fungi have this type of nutrition. |
Chap 6 - Life Processes - P101 - Q2
Where do plants get each of the raw materials required for photosynthesis?
Chap 6 - Life Processes - P101 - Q3
What is the role of the acid in our stomach?
Chap 6 - Life Processes - P101 - Q4
What is the function of digestive enzymes?
Chap 6 - Life Processes - P101 - Q5
How is the small intestine designed to absorb digested food?
Chap 6 - Life Processes - P105 - Q1
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Chap 6 - Life Processes - P105 - Q2
What are the different ways in which glucose is oxidized to provide energy in various organisms?
Chap 6 - Life Processes - P105 - Q3
How is oxygen and carbon dioxide transported in human beings?
Chap 6 - Life Processes - P105 - Q4
How are the lungs designed in human beings to maximize the area for exchange of gases?
Chap 6 - Life Processes - P110 - Q1
What are the components of the transport system in human beings? What are the functions of these components?
Chap 6 - Life Processes - P110 - Q2
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Chap 6 - Life Processes - P110 - Q3
What are the components of the transport system in highly organised plants?
Chap 6 - Life Processes - P110 - Q4
How are water and minerals transported in plants?
Chap 6 - Life Processes - P110 - Q5
How is food transported in plants?
Chap 6 - Life Processes - P112 - Q1
Describe the structure and functioning of nephrons.
Chap 6 - Life Processes - P112 - Q2
What are the methods used by plants to get rid of excretory products?
Chap 6 - Life Processes - P112 - Q3
How is the amount of urine produced regulated?
Chap 6 - Life Processes - P113 - Q1
The kidneys in human beings are a part of the system for
(a) nutrition.
(b) respiration.
(c) excretion.
(d) transportation.
Chap 6 - Life Processes - P113 - Q2
The xylem in plants are responsible for
(a) transport of water.
(b) transport of food.
(c) transport of amino acids.
(d) transport of oxygen.
Chap 6 - Life Processes - P113 - Q3
The autotrophic mode of nutrition requires
(a) carbon dioxide and water.
(b) chlorophyll.
(c) sunlight.
(d) all of the above.
Chap 6 - Life Processes - P113 - Q4
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.
Chap 6 - Life Processes - P113 - Q5
How are fats digested in our bodies? Where does this process take place?
Chap 6 - Life Processes - P113 - Q6
What is the role of saliva in the digestion of food?
Chap 6 - Life Processes - P113 - Q7
What are the necessary conditions for autotrophic nutrition and what are its by-products?
Chap 6 - Life Processes - P113 - Q8
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Chap 6 - Life Processes - P113 - Q9
How are the alveoli designed to maximise the exchange of gases?
Chap 6 - Life Processes - P113 - Q10
What would be the consequences of a deficiency of haemoglobin in our bodies?
Chap 6 - Life Processes - P113 - Q11
Describe double circulation in human beings. Why is it necessary?
Chap 6 - Life Processes - P113 - Q12
What are the differences between the transport of materials in xylem and phloem?
Chap 7 - Control and Coordination
Chap 7 - Control and Coordination - P119 - Q1
What is the difference between a reflex action and walking?
A reflex action is a Sudden action in response to something in the environment. In Other hand,Walking, is a voluntary action. It is under our conscious control
Chap 7 - Control and Coordination - P119 - Q2
What happens at the synapse between two neurons?
A chemical reaction that creates an electrical impulse. This impulse travels from the endrite to the cell body, and then along the axon to its end. At the end of the axon, the electrical impulse sets off the release of some chemicals. These chemicals cross the
gap, or synapse, and start a similar electrical impulse in a dendrite of the next neuron.
Chap 7 - Control and Coordination - P119 - Q3
Which part of the brain maintains posture and equilibrium of the body?
Cerebellum, is the part of the brain maintains posture and equilibrium of the body.
Chap 7 - Control and Coordination - P119 - Q4
How do we detect the smell of an agarbatti (incense stick)?
There are separate areas of association where this sensory information is
interpreted by putting it together with information from other receptors
as well as with information that is already stored in the brain. Based on
all this, a decision is made about how to respond and the information is
passed on to the motor areas which control the movement of voluntary
muscles,
Chap 7 - Control and Coordination - P119 - Q5
What is the role of the brain in reflex action?
commonly when we talk about some sudden action in response to something in the environment. this is the case, it is no surprise that the thinking tissue in our body consists of dense networks of intricately arranged neurons. It sits in the forward end of the skull, and receives signals from all over the body which it thinks about before responding to them. Obviously, in order to receive these signals, this thinking part of the brain in the skull must be connected to nerves coming from various parts of the body. Similarly, if this part of the brain is to instruct muscles to move, nerves must carry this signal back to different parts of the body.
Chap 7 - Control and Coordination - P122 - Q1
What are plant hormones?
coordinate growth, development and responses to the environment. They are synthesised at places away from where they act and simply diffuse to the area of action.
Chap 7 - Control and Coordination - P122 - Q2
How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
The movement of leaves of the sensitive plant, “touch me not”, touch or contact stimuli. Plants show tropism in response to other stimuli as well. The roots of a plant occurs in response to always grow downwards while the shoots usually grow
upwards and away from the earth.
Chap 7 - Control and Coordination - P122 - Q3
Give an example of a plant hormone that promotes growth.
Auxin is an example of growth-promoting plant hormone.
Chap 7 - Control and Coordination - P122 - Q4
How do auxins promote the growth of a tendril around a support?
It help in the growth of the stem. Cytokinins promote cell division, and it is natural then that they are present in greater concentration in
areas of rapid cell division, such as in fruits and seeds
Chap 7 - Control and Coordination - P122 - Q5
Design an experiment to demonstrate hydrotropism.
Take two small beakers and label them as A and B. Fill beaker A with water. Now make a cylindrical-shaped roll from a filter paper and keep it as a bridge between beaker A and beaker B, as shown in the figure. Attach few germinating seeds in the middle of the filter paper bridge. Now, cover the entire set-up with a transparent plastic container so that the moisture is retained.
(IMAGES)
Observation:
The roots of the germinating seeds will grow towards beaker A.
(IMAGES)
This experiment demonstrates the phenomenon of hydrotropism.
Chap 7 - Control and Coordination - P125 - Q1
How does chemical coordination take place in animals?
A chemical signal were to be sent as well, it would reach all cells of the body and provide the wideranging changes needed. This is done in many animals, including human beings, using a hormone called adrenaline that is secreted from the adrenal glands.
Chap 7 - Control and Coordination - P125 - Q1
Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin
(d) Cytokinin
Chap 7 - Control and Coordination - P125 - Q2
Why is the use of iodised salt advisable?
Iodine is necessary for the thyroid gland to make thyroxin hormone. Thyroxin regulates carbohydrate, protein and fat metabolism in the body so as to provide the best balance for growth.
Chap 7 - Control and Coordination - P125 - Q2
The gap between two neurons is called a
(a) dendrite.
(b) synapse.
(c) axon.
(d) impulse.
(b) synapse.
Chap 7 - Control and Coordination - P125 - Q3
How does our body respond when adrenaline is secreted into the blood?
Adrenaline is secreted directly into the blood and carried to different parts of the body. The target organs or the specific tissues on which it
acts include the heart. As a result, the heart beats faster, resulting in supply of more oxygen to our muscles
Chap 7 - Control and Coordination - P126 - Q3
The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
(d) The brain is responsible for thinking, regulating the heart beat and balancing the body.
Chap 7 - Control and Coordination - P126 - Q4
Why are some patients of diabetes treated by giving injections of insulin?
The function of receptors are usually located in our sense organs, such as the
inner ear, the nose, the tongue, and so on.
It sits in the forward end of the skull, and receives signals from all over the
body which it thinks about before responding to them. Obviously, in
order to receive these signals, this thinking part of the brain in the skull
must be connected to nerves coming from various parts of the body.
Chap 7 - Control and Coordination - P126 - Q5
Draw the structure of a neuron and explain its function.
Neurons are the functional units of the nervous system. The three main parts of a neuron are axon, dendrite, and cell body.
(IMAGES)
Functions of the three parts of a neuron:
Axon: It conducts messages away from the cell body.
Dendrite: It receives information from axon of another cell and conducts the messages towards the cell body.
Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with the maintenance and growth.
Chap 7 - Control and Coordination - P126 - Q6
How does phototropism occur in plants?
Environmental triggers such as light, or gravity will change the directions that plant parts grow in. These directional, or tropic, movements can be either towards the stimulus, or away from it. So, in two different kinds of phototropic movement, shoots respond by bending towards light while roots respond by bending away from it.
Chap 7 - Control and Coordination - P126 - Q7
Which signals will get disrupted in case of a spinal cord injury?
In case of any injury to the spinal cord, the signals coming from the nerves as well as the signals coming to the receptors will be disrupted.
Chap 7 - Control and Coordination - P126 - Q8
How does chemical coordination occur in plants?
cells around have the means to detect this compound using special molecules on their surfaces, then they would be able to recognise information, and even transmit it. This will be slower, of course, but it can potentially reach all cells of the body, regardless of nervous connections, and it can be done steadily and persistently. These compounds, or hormones used by multicellular organisms for control and coordination show a great deal of diversity,
Chap 7 - Control and Coordination - P126 - Q9
What is the need for a system of control and coordination in an organism?
This information, acquired at the end of the dendritic tip of a nerve cell sets off a chemical reaction that creates an electrical impulse. This impulse travels from the dendrite to the cell body, and then along the axon to its end. At the end of the axon, the electrical impulse sets off the release of some chemicals. These chemicals cross the
gap, or synapse, and start a similar electrical impulse in a dendrite of the next
neuron. This is a general scheme of how nervous impulses travel in the body. A similar synapse finally allows delivery of such impulses from neurons to other cells, such as muscles cells or gland
Chap 7 - Control and Coordination - P126 - Q10
How are involuntary actions and reflex actions different from each other?
Involuntary actions cannot be consciously controlled. On the other hand, the reflex actions such as closing of eyes immediately when bright light is focused show sudden response and do not involve any thinking. This means that unlike involuntary actions, the reflex actions are not under the control of brain.
Chap 7 - Control and Coordination - P126 - Q11
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
|
|
Nervous system mechanism |
|
Hormonal system mechanism |
|
1. |
The information is contained in the form of electric impulse. |
1. |
The information is contained in the form of chemical messengers. |
|
2. |
The axons and dendrites trasfer the information through a coordinated effort. |
2. |
The information is transferred or transported through blood. |
|
3. |
The flow of information is huge and the response is quick. |
3. |
The information travels slowly and the response is slow. |
|
4. |
Its effects are short lived. |
4. |
It has prolonged effects. |
Chap 7 - Control and Coordination - P126 - Q12
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
|
|
Movement in sensitive plants |
|
Movement in our legs |
|
1. |
The movement that takes place in a sensitive plant such as Mimosa pudica occurs in response to touch (stimulus). |
1. |
Movement in our legs is an example of voluntary actions. |
|
2. |
For this movement, the information is transmitted from cell to cell by electro-chemical signals as plants do not have any specialised tissue for conduction of impulses. |
2. |
The signal or messages for these actions are passed to the brain and hence are consciously controlled. |
|
3. |
For this movement to occur, the plant cells change shape by changing the amount of water in them. |
3. |
In animal muscle cells, some proteins are found which allow the movement to occur. |
Chap 8 - How do Organisms Reproduce?
Chap 8 - How do Organisms Reproduce? - P128 - Q1
What is the importance of DNA copying in reproduction?
DNA copying during reproduction is important for the maintenance of body design features that allow the organism to use that particular niche. Reproduction is therefore linked to the stability of populations of species. However, niches can change because of reasons beyond the control of the organisms. Temperatures on earth can go up or down, water levels can vary, or there could be meteorite hits, to think of a few examples. If
a population of reproducing organisms were suited to a particular niche and if the niche were drastically altered, the population could be wiped out. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.
Chap 8 - How do Organisms Reproduce? - P128 - Q2
Why is variation beneficial to the species but not necessarily for the individual?
Variations are beneficial to the species than individual because sometimes for a species, the environmental conditions change so drastically that their survival becomes difficult.
Chap 8 - How do Organisms Reproduce? - P133 - Q1
How does binary fission differ from multiple fission?
In binary fission, a single cell divides into two equal halves. Amoeba and
Bacteria divide by binary fission
In multiple fission, a single cell divides into many daughter cells simultaneously. Amoeba and Plasmodium divide by multiple fission
Chap 8 - How do Organisms Reproduce? - P133 - Q2
How will an organism be benefited if it reproduces through spores?
• Large numbers of spores are produced in one sporangium.
• Spores are distributed easily by air to far-off places to avoid competition at one place.
• Spores are covered by thick walls to prevent dehydration under unfavourable conditions
Chap 8 - How do Organisms Reproduce? - P133 - Q3
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
The process of regeneration involves the formation of new organisms from its body parts. Simple organisms can utilize this method of reproduction as their entire body is made of similar kind of cells in which any part of their body can be formed by growth and development. They can regenerate their lost body parts such as skin, muscles, blood, etc. However, they cannot give rise to new individuals through regeneration
Chap 8 - How do Organisms Reproduce? - P133 - Q4
Why is vegetative propagation practised for growing some types of plants?
The ability of the plants to reproduce by producing new plants from the vegetative plant parts such as leaf, stem, or roots under appropriate conditions However, this method of reproduction is also used for agricultural purposes in commercial production of some plants such as sugarcane, grapes, roses, etc.
Chap 8 - How do Organisms Reproduce? - P133 - Q5
Why is DNA copying an essential part of the process of reproduction?
DNA (Deoxyribonucleic acid) copying is an essential part of reproduction as it passes genetic information from parents to offspring. It determines the body design of an individual. The reproducing cells produce a copy of their DNA through some chemical reactions and result in two copies of DNA. The copying of DNA always takes place along with the creation of additional cellular structure. This process is then followed by division of a cell to form two cells.
Chap 8 - How do Organisms Reproduce? - P140 - Q1
How is the process of pollination different from fertilization?
transfer of pollens from anther to stigma. It occurs with the help of certain pollinators such as air, water, birds, or some insects.
Fertilization, on the other hand, is the fusion of the male and female gametes.
Chap 8 - How do Organisms Reproduce? - P140 - Q2
What is the role of the seminal vesicles and the prostate gland?
seminal vesicles and prostate glands lubricate the sperms and provide a fluid medium for easy transport of sperms
Chap 8 - How do Organisms Reproduce? - P140 - Q3
What are the changes seen in girls at the time of puberty?
Secondary sexual characteristics in girls:
• Increase in the size of uterus and ovary.
• Beginning of menstrual cycle.
• More secretion of oil from the skin, which results in the appearance of pimples.
Chap 8 - How do Organisms Reproduce? - P140 - Q4
How does the embryo get nourishment inside the mother’s body?
The embryo develops inside the mother’s body for about nine months. Inside the uterus, the outer tissue surrounding the embryo develops finger-like projections called villi. These villi are surrounded by uterine tissue and maternal blood.
Chap 8 - How do Organisms Reproduce? - P140 - Q5
If a woman is using a copper−T, will it help in protecting her from sexually transmitted diseases?
No. Using a copper-T will not provide a protection from sexually transmitted diseases, as it does not prevent the entry of semen.
Chap 8 - How do Organisms Reproduce? - P141 - Q1
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania
(b) Asexual reproduction takes place through budding in yeast
Chap 8 - How do Organisms Reproduce? - P141 - Q2
Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
(c) Vas deferens is not a part of the female reproductive system in human beings.
Chap 8 - How do Organisms Reproduce? - P141 - Q3
The anther contains
(a) sepals.
(b) ovules.
(c) carpel.
(d) pollen grains.
(d) The anther contains pollen grains
Chap 8 - How do Organisms Reproduce? - P141 - Q4
What are the advantages of sexual reproduction over asexual reproduction?
Advantages of sexual reproduction:
• In sexual reproduction, more variations are produced. Thus, it ensures survival of species in a population.
• The new formed individual has characteristics of both the parents.
• Variations are more viable in sexual mode than in asexual one. This is because in asexual reproduction, DNA has to function inside the inherited cellular apparatus.
Chap 8 - How do Organisms Reproduce? - P141 - Q5
What are the functions performed by the testis in human beings?
• Produce sperms
• Produce a hormone called testosterone, which brings about secondary sexual characters in boys
Chap 8 - How do Organisms Reproduce? - P141 - Q6
Why does menstruation occur?
process occurs every month because one egg is released from the ovary every month and at the same time, the uterus (womb) prepares itself to receive the fertilized egg. Thus, the inner lining of the uterus gets thickened and is supplied with blood to nourish the embryo.
Chap 8 - How do Organisms Reproduce? - P141 - Q7
Draw a labelled diagram of the longitudinal section of a flower.
Chap 8 - How do Organisms Reproduce? - P141 - Q8
What are the different methods of contraception?
Natural method:
It involves avoiding the chances of meeting of sperms and ovum. In this method, the sexual act is avoided from day 10th to 17th of the menstrual cycle because during this period,
Barrier method : Barriers are available for both males and females. Condoms are barriers made of thin rubber that are used to cover penis in males and vagina in females.
Oral contraceptives: These contain small doses of hormones that prevent the release of eggs and thus fertilization cannot occur
Implants and surgical methods: It includes the blocking of vas deferens to prevent the transfer of sperms known as vasectomy. Similarly, fallopian tubes of the female can be blocked so that the egg will not reach the uterus known as tubectomy.
Chap 8 - How do Organisms Reproduce? - P141 - Q9
How are the modes for reproduction different in unicellular and multicellular organisms?
In unicellular organisms, The modes of reproduction in unicellular organisms can be fission, budding, etc. whereas in multicellular organisms, they can reproduce by complex reproductive methods such as vegetative propagation, spore formation, etc.
Chap 8 - How do Organisms Reproduce? - P141 - Q10
How does reproduction help in providing stability to populations of species?
It helps in providing stability to the population of species by producing a new individual that resembles the parents. This is the reason why cats give birth to only cats or dogs give birth to only dogs. Therefore, reproduction provides stability to populations of dogs or cats or any other species
Chap 8 - How do Organisms Reproduce? - P141 - Q11
What could be the reasons for adopting contraceptive methods?
(i) To prevent unwanted pregnancies.
(ii) To control population rise or birth rate.
(iii) To prevent the transfer of sexually transmitted diseases
Chap 9 - Heredity and Evolution
Chap 9 - Heredity and Evolution - P143 - Q1
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
In asexual reproduction, the reproducing cells manufacture a copy of their DNA through some chemical reactions. However, this copying of DNA is not perfect.
if a trait is present in only 10% of the population, it is more likely that the trait has arisen recently. Hence, it can be concluded that trait B that exists in 60% of the same population has arisen earlier than trait A.
Chap 9 - Heredity and Evolution - P143 - Q2
How does the creation of variations in a species promote survival?
Chap 9 - Heredity and Evolution - P147 - Q1
How do Mendel’s experiments show that traits may be dominant or recessive?
Chap 9 - Heredity and Evolution - P147 - Q2
How do Mendel’s experiments show that traits are inheritedindependently?
Chap 9 - Heredity and Evolution - P147 - Q3
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits − blood group A or O − is dominant? Why or why not?
Chap 9 - Heredity and Evolution - P147 - Q4
How is the sex of the child determined in human beings?
Chap 9 - Heredity and Evolution - P150 - Q1
What are the different ways in which individuals with a particular trait may increase in a population?
Chap 9 - Heredity and Evolution - P150 - Q2
Why are traits acquired during the life-time of an individual not inherited?
Chap 9 - Heredity and Evolution - P150 - Q3
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?
Chap 9 - Heredity and Evolution - P151 - Q1
What factors could lead to the rise of a new species?
Chap 9 - Heredity and Evolution - P151 - Q2
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?
Chap 9 - Heredity and Evolution - P151 - Q3
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
Chap 9 - Heredity and Evolution - P156 - Q1
Give an example of characteristics being used to determine how close two species are in evolutionary terms.
Chap 9 - Heredity and Evolution - P156 - Q2
Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not?
Chap 9 - Heredity and Evolution - P156 - Q3
What are fossils? What do they tell us about the process of evolution?
Chap 9 - Heredity and Evolution - P158 - Q1
Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?
Chap 9 - Heredity and Evolution - P158 - Q2
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not?
Chap 9 - Heredity and Evolution - P159 - Q1
A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw
Chap 9 - Heredity and Evolution - P159 - Q2
An example of homologous organs is
(a) our arm and a dog’s fore-leg.
(b) our teeth and an elephant’s tusks.
(c) potato and runners of grass.
(d) all of the above.
Chap 9 - Heredity and Evolution - P159 - Q3
In evolutionary terms, we have more in common with
(a) a Chinese school-boy.
(b) a chimpanzee.
(c) a spider.
(d) a bacterium.
Chap 9 - Heredity and Evolution - P159 - Q4
A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?
Chap 9 - Heredity and Evolution - P159 - Q5
How are the areas of study − evolution and classification − interlinked?
Chap 9 - Heredity and Evolution - P159 - Q6
Explain the terms analogous and homologous organs with examples.
Chap 9 - Heredity and Evolution - P159 - Q7
Outline a project which aims to find the dominant coat colour in dogs.
Chap 9 - Heredity and Evolution - P159 - Q8
Explain the importance of fossils in deciding evolutionary relationships.
Chap 9 - Heredity and Evolution - P159 - Q9
What evidence do we have for the origin of life from inanimate matter?
Chap 9 - Heredity and Evolution - P159 - Q10
Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Chap 9 - Heredity and Evolution - P159 - Q11
How is the equal genetic contribution of male and female parents ensured in the progeny?
Chap 10 - Light – Reflection and Refraction
Chap 10 - Light – Reflection and Refraction - P168 - Q1
Define the principal focus of a concave mirror
Concave mirror converge at a specific point on its principal axis after reflecting from the mirror. This point is known as the principal focus of the concave mirror.
Chap 10 - Light – Reflection and Refraction - P168 - Q2
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
Radius of curvature, R = 20 cm
Radius of curvature of a spherical mirror = 2 × Focal length (f)
R = 2f
Hence, the focal length of the given spherical mirror is 10 cm.
Chap 10 - Light – Reflection and Refraction - P168 - Q3
Name the mirror that can give an erect and enlarged image of an object.
concave mirror, is the image formed is virtual, erect, and enlarged.
Chap 10 - Light – Reflection and Refraction - P168 - Q4
Why do we prefer a convex mirror as a rear-view mirror in vehicles?
It is preferred as a rear-view mirror in vehicles because they give a wider field of view, which allows the driver to see most of the traffic behind him.
Chap 10 - Light – Reflection and Refraction - P171 - Q1
Find the focal length of a convex mirror whose radius of curvature is 32 cm.
Radius of curvature, R = 32 cm
Radius of curvature = 2 × Focal length (f)
R = 2f
Hence, the focal length of the given convex mirror is 16 cm.
Chap 10 - Light – Reflection and Refraction - P171 - Q2
A concave mirror produces three times magnified (enlarged) real image of object placed at 10 cm in front of it. Where is the image located?
Let the height of the object, ho = h
Then, height of the image, hI = −3h (Image formed is real)
Object distance, u = −10 cm
v = 3 × (−10) = −30 cm
Here, the negative sign indicates that an inverted image is formed at a distance of
30 cm in front of the given concave mirror.
Chap 10 - Light – Reflection and Refraction - P176 - Q1
A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Why?
The light ray bends towards the normal.
water is optically denser than air, a ray of light travelling from air into the water will bend towards the normal.
Chap 10 - Light – Reflection and Refraction - P176 - Q2
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
Speed of light in vacuum, c = 3 × 108 m s−1
Refractive index of glass, ng = 1.50
Speed of light in the glass,
Chap 10 - Light – Reflection and Refraction - P176 - Q3
Find out, from Table, the medium having highest optical density. Also find the medium with lowest optical density.
|
Material medium |
Refractive index |
Material medium |
Refractive index |
|
Air |
1.0003 |
Canada Balsam |
1.53 |
|
Ice |
1.31 |
- |
- |
|
Water |
1.33 |
Rock salt |
1.54 |
|
Alcohol |
1.36 |
- |
- |
|
Kerosene |
1.44 |
Carbon disulphide |
1.63 |
|
Fused quartz |
1.46 |
Dense flint glass |
1.65 |
|
Turpentine oil |
1.47 |
Ruby |
1.71 |
|
Benzene |
1.50 |
Sapphire |
1.77 |
|
Crown glass |
1.52 |
Diamond |
2.42 |
A medium which has the highest refractive index will have the highest optical density and vice-versa.
diamond and air respectively have the highest and lowest refractive index. Therefore, diamond has the highest optical density and air has the lowest optical density.
Chap 10 - Light – Reflection and Refraction - P176 - Q4
You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table.
|
Material medium |
Refractive index |
Material medium |
Refractive index |
|
Air |
1.0003 |
Canada Balsam |
1.53 |
|
Ice |
1.31 |
- |
- |
|
Water |
1.33 |
Rock salt |
1.54 |
|
Alcohol |
1.36 |
- |
- |
|
Kerosene |
1.44 |
Carbon disulphide |
1.63 |
|
Fused quartz |
1.46 |
Dense flint glass |
1.65 |
|
Turpentine oil |
1.47 |
Ruby |
1.71 |
|
Benzene |
1.50 |
Sapphire |
1.77 |
|
Crown glass |
1.52 |
Diamond |
2.42 |
It can be inferred from the relation that light will travel the slowest in the material which has the highest refractive index and travel the fastest in the material which has the lowest refractive index.
It can be observed from table 10.3 that the refractive indices of kerosene, turpentine, and water are 1.44, 1.47, and 1.33 respectively. Therefore, light travels the fastest in water.
Chap 10 - Light – Reflection and Refraction - P176 - Q5
The refractive index of diamond is 2.42. What is the meaning of this statement?
Where, c is the speed of light in vacuum/air
The refractive index of diamond is 2.42. This suggests that the speed of light in diamond will reduce by a factor 2.42 compared to its speed in air.
Chap 10 - Light – Reflection and Refraction - P184 - Q1
Define 1 dioptre of power of a lens.
The S.I. unit of power of a lens is Dioptre. It is denoted by D.
1 dioptre is defined as the power of a lens of focal length 1 metre.
∴1 D = 1 m−1
Chap 10 - Light – Reflection and Refraction - P184 - Q2
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
It is given that the image of the needle is formed at a distance of 50 cm from the convex lens. Hence, the needle is placed in front of the lens at a distance of
50 cm.
Object distance, u = −50 cm
Image distance, v = 50 cm
Focal length = f
According to the lens formula,
Hence, the power of the given lens is +4 D.
Chap 10 - Light – Reflection and Refraction - P184 - Q3
Find the power of a concave lens of focal length 2 m.
Focal length of concave lens, f = 2 m
Here, negative sign arises due to the divergent nature of concave lens.
Hence, the power of the given concave lens is −0.5 D.
Chap 10 - Light – Reflection and Refraction - P185 - Q1
Which one of the following materials cannot be used to make a lens?
(a) Water
(b) Glass
(c) Plastic
(d) Clay
(d) Clay
Chap 10 - Light – Reflection and Refraction - P185 - Q2
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
(a) Between the principal focus and the centre of curvature
(b) At the centre of curvature
(c) Beyond the centre of curvature
(d) Between the pole of the mirror and its principal focus.
(d) Between the pole of the mirror and its principal focus.
Chap 10 - Light – Reflection and Refraction - P185 - Q3
Where should an object be placed in front of a convex lens to get a real image of the size of the object?
(a) At the principal focus of the lens
(b) At twice the focal length
(c) At infinity
(d) Between the optical centre of the lens and its principal focus.
(b) At twice the focal length
Chap 10 - Light – Reflection and Refraction - P185 - Q4
A spherical mirror and a thin spherical lens have each a focal length of −15 cm. The mirror and the lens are likely to be
(a) both concave
(b) both convex
(c) the mirror is concave and the lens is convex
(d) the mirror is convex, but the lens is concave
(a) both concave
Chap 10 - Light – Reflection and Refraction - P186 - Q5
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be
(a) plane
(b) concave
(c) convex
(d) either plane or convex
(d) either plane or convex
Chap 10 - Light – Reflection and Refraction - P186 - Q6
Which of the following lenses would you prefer to use while reading small letters found in a dictionary?
(a) A convex lens of focal length 50 cm
(b) A concave lens of focal length 50 cm
(c) A convex lens of focal length 5 cm
(d) A concave lens of focal length 5 cm
(c) A convex lens of focal length 5 cm
Chap 10 - Light – Reflection and Refraction - P186 - Q7
We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.
A concave mirror gives an erect image when an object is placed between its pole (P) and the principal focus (F).
Hence, to obtain an erect image of an object from a concave mirror of focal length 15 cm, the object must be placed anywhere between the pole and the focus. The image formed will be virtual, erect, and magnified in nature
Chap 10 - Light – Reflection and Refraction - P186 - Q8
Name the type of mirror used in the following situations.
(a) Headlights of a car
(b) Side/rear-view mirror of a vehicle
(c) Solar furnace
Support your answer with reason.
(a) Concave (b) Convex (c) Concave
Explanation
(a) Concave mirror is used in the headlights of a car. This is because concave mirrors can produce powerful parallel beam of light when the light source is placed at their principal focus.
(b) Convex mirror is used in side/rear view mirror of a vehicle. Convex mirrors give a virtual, erect, and diminished image of the objects placed in front of it. Because of this, they have a wide field of view. It enables the driver to see most of the traffic behind him/her.
(c) Concave mirrors are convergent mirrors. That is why they are used to construct solar furnaces. Concave mirrors converge the light incident on them at a single point known as principal focus. Hence, they can be used to produce a large amount of heat at that point.
Chap 10 - Light – Reflection and Refraction - P186 - Q9
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
The convex lens will form complete image of an object, even if its one half is covered with black paper. It can be understood by the following two cases.
Case I
When the upper half of the lens is covered
In this case, a ray of light coming from the object will be refracted by the lower half of the lens. These rays meet at the other side of the lens to form the image of the given object.
Case II
When the lower half of the lens is covered
In this case, a ray of light coming from the object is refracted by the upper half of the lens. These rays meet at the other side of the lens to form the image of the given object.
Chap 10 - Light – Reflection and Refraction - P186 - Q10
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.
According to the lens formula,
The positive value of v shows that the image is formed at the other side of the lens.
The negative sign shows that the image is real and formed behind the lens.
The negative value of image height indicates that the image formed is inverted.
Chap 10 - Light – Reflection and Refraction - P186 - Q11
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
According to the lens formula,
The negative value of u indicates that the object is placed 30 cm in front of the lens.
Chap 10 - Light – Reflection and Refraction - P186 - Q12
An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.
According to the mirror formula,
v
The positive value of v indicates that the image is formed behind the mirror.
The positive value of magnification indicates that the image formed is virtual and erect.
Chap 10 - Light – Reflection and Refraction - P186 - Q13
The magnification produced by a plane mirror is +1. What does this mean?
The magnification produced by a plane mirror is +1. It shows that the image formed by the plane mirror is of the same size as that of the object. The positive sign shows that the image formed is virtual and erect.
Chap 10 - Light – Reflection and Refraction - P186 - Q14
An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size
According to the mirror formula,
The positive value of v indicates that the image is formed behind the mirror.
The positive value of image height indicates that the image formed is erect.
Therefore, the image formed is virtual, erect, and smaller in size.
Chap 10 - Light – Reflection and Refraction - P186 - Q15
An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed, so that a sharp focused image can be obtained? Find the size and the nature of the image.
According to the mirror formula,
The screen should be placed at a distance of 54 cm in front of the given mirror.
The negative value of magnification indicates that the image formed is real.
The negative value of image height indicates that the image formed is inverted.
Chap 10 - Light – Reflection and Refraction - P186 - Q16
Find the focal length of a lens of power −2.0 D. What type of lens is this?
A concave lens has a negative focal length. Hence, it is a concave lens.
Chap 10 - Light – Reflection and Refraction - P186 - Q17
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
A convex lens has a positive focal length. Hence, it is a convex lens or a converging lens
Chap 11 - Human Eye and Colourful World
Chap 11 - Human Eye and Colourful World - P190 - Q1
What is meant by power of accommodation of the eye?
The ciliary muscles contract making the eye lens thicker. Thus, the focal length of the eye lens decreases and the nearby objects become visible to the eyes. Hence, the human eye lens is able to adjust its focal length to view both distant and nearby objects on the retina. This ability is called the power of accommodation of the eyes.
Chap 11 - Human Eye and Colourful World - P190 - Q2
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
Because the image of an object beyond 1.2 m is formed in front of the retina and not at the retina, as shown in the given figure.
To correct this defect of vision, he must use a concave lens. The concave lens will bring the image back to the retina as shown in the given figure.
Chap 11 - Human Eye and Colourful World - P190 - Q3
What is the far point and near point of the human eye with normal vision?
The minimum distance of the object from the eye, which can be seen distinctly without strain. For a normal human eye, this distance is 25 cm. is called near point of the human eye.
The maximum distance to which the eye can see the objects clearly. The far point of the normal human eye is infinity is called the far point of the eye.
Chap 11 - Human Eye and Colourful World - P190 - Q4
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
It shows that he is unable to see distant objects clearly. He is suffering from myopia. This defect can be corrected by using a concave lens.
Chap 11 - Human Eye and Colourful World - P197 - Q1
The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to
(a) presbyopia
(b) accommodation
(c) near-sightedness
(d) far-sightedness
(b) accommodation
Chap 11 - Human Eye and Colourful World - P198 - Q2
The human eye forms the image of an object at its
(a) cornea (b) iris (c) pupil (d) retina
(d) retina
Chap 11 - Human Eye and Colourful World - P198 - Q3
The least distance of distinct vision for a young adult with normal vision is about
(a) 25 m
(b) 2.5 cm
(c) 25 cm
(d) 2.5 m
(c) 25 cm
Chap 11 - Human Eye and Colourful World - P198 - Q4
The change in focal length of an eye lens is caused by the action of the
(a) pupil
(b) retina
(c) ciliary muscles
(d) iris
(c) ciliary muscles
Chap 11 - Human Eye and Colourful World - P198 - Q5
A person needs a lens of power −5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?
For distant vision = −0.181 m, for near vision = 0.667 m
The power P of a lens of focal length f is given by the relation
(i) Power of the lens used for correcting distant vision = −5.5 D
Focal length of the required lens, f =
The focal length of the lens for correcting distant vision is −0.181 m.
(ii) Power of the lens used for correcting near vision = +1.5 D
Focal length of the required lens, f =
The focal length of the lens for correcting near vision is 0.667 m.
Chap 11 - Human Eye and Colourful World - P198 - Q6
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
The convex lens actually creates a virtual image of a nearby object (N’ in the figure) at the near point of vision (N) of the person suffering from hypermetropia.
The given person will be able to clearly see the object kept at 25 cm (near point of the normal eye), if the image of the object is formed at his near point, which is given as 1 m.
Object distance, u = −25 cm
Image distance, v = −1 m = −100 m
Focal length, f
Using the lens formula,
A convex lens of power +3.0 D is required to correct the defect.
Chap 11 - Human Eye and Colourful World - P198 - Q7
Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
A normal eye is unable to clearly see the objects placed closer than 25 cm because the ciliary muscles of eyes are unable to contract beyond a certain limit.
If the object is placed at a distance less than 25 cm from the eye, then the object appears blurred and produces strain in the eyes.
Chap 11 - Human Eye and Colourful World - P198 - Q8
Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
If the object is placed at a distance less than 25 cm from the eye, then the object appears blurred and produces strain in the eyes.
Chap 11 - Human Eye and Colourful World - P198 - Q9
What happens to the image distance in the eye when we increase the distance of an object from the eye?
When we increase the distance of an object from the eye, the image distance in the eye does not change. The increase in the object distance is compensated by the change in the focal length of the eye lens. The focal length of the eyes changes in such a way that the image is always formed at the retina of the eye
Chap 11 - Human Eye and Colourful World - P198 - Q10
Why do stars twinkle?
When the light coming from stars enters the earth’s atmosphere, it gets refracted at different levels because of the variation in the air density at different levels of the atmosphere. When the star light refracted by the atmosphere comes more towards us, it appears brighter than when it comes less towards us. Therefore, it appears as if the stars are twinkling at night.
Chap 11 - Human Eye and Colourful World - P198 - Q11
Explain why the planets do not twinkle?
The different parts of these planets produce either brighter or dimmer effect in such a way that the average of brighter and dimmer effect is zero. Hence, the twinkling effects of the planets are nullified and they do not twinkle.
Chap 11 - Human Eye and Colourful World - P198 - Q12
Why does the Sun appear reddish early in the morning?
Blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light. Therefore, the Sun appears reddish early in the morning.
Chap 11 - Human Eye and Colourful World - P198 - Q13
Why does the sky appear dark instead of blue to an astronaut?
There is no atmosphere in the outer space that can scatter the sunlight. As the sunlight is not scattered, no scattered light reach the eyes of the astronauts and the sky appears black to them.
Chap 12 - Electricity
Chap 12 - Electricity - P200 - Q1
What does an electric circuit mean?
A switch makes a conducting link between the cell and the bulb. A continuous and closed path of an electric current is called an electric circuit.
Chap 12 - Electricity - P200 - Q2
Define the unit of current.
The electric current is expressed by a unit called ampere (A), One ampere is
constituted by the flow of one coulomb of charge per second,
Chap 12 - Electricity - P200 - Q3
Calculate the number of electrons constituting one coulomb of charge.
1 electron possesses a charge of 1.6 × 10−19 C, i.e., 1.6 × 10−19 C of charge is contained in 1 electron.
∴ 1 C of charge is contained in
Therefore, electrons constitute one coulomb of charge.
Chap 12 - Electricity - P202 - Q1
Name a device that helps to maintain a potential difference across a conductor.
cell, battery, power supply, etc. helps to maintain a potential difference across a conductor.
Chap 12 - Electricity - P202 - Q2
What is meant by saying that the potential difference between two points is 1 V?
If 1 J of work is required to move a charge of amount 1 C from one point to another, then it is said that the potential difference between the two points is 1 V.
Chap 12 - Electricity - P202 - Q3
How much energy is given to each coulomb of charge passing through a 6 V battery?
Energy given to each coulomb of charge is equal to the amount of work required to move it. The amount of work is given by the expression,
Potential difference =
Where,
Charge = 1 C
Potential difference = 6 V
Therefore, 6 J of energy is given to each coulomb of charge passing through a battery of 6 V.
Chap 12 - Electricity - P209 - Q1
On what factors does the resistance of a conductor depend?
The resistance of the conductor depends (i) on its length, (ii) on its area of cross-section, and (iii) on the nature of its material. Precise measurements have shown that resistance of a uniform metallic conductor is directly proportional to its length
Chap 12 - Electricity - P209 - Q2
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
Resistance of a wire,
Where,
= Resistivity of the material of the wire
l = Length of the wire
A = Area of cross-section of the wire
Resistance is inversely proportional to the area of cross-section of the wire.
Thicker the wire, lower is the resistance of the wire and vice-versa. Therefore, current can flow more easily through a thick wire than a thin wire.
Chap 12 - Electricity - P209 - Q3
Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?
According to Ohm’s law
V = IR
Where,
Resistance of the electrical component = R
Potential difference = V
Current = I
The potential difference is reduced to half, keeping resistance constant.
Let the new resistance be R' and the new amount of current be I '.
Therefore, from Ohm’s law, we obtain the amount of new current.
Therefore, the amount of current flowing through the electrical component is reduced by half.
Chap 12 - Electricity - P209 - Q4
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Because an alloy is higher than the pure metal. Moreover, at high temperatures, the alloys do not melt readily.
Chap 12 - Electricity - P209 - Q5
Use the data in Table 12.2 to answer the following −
Table 12.2 Electrical resistivity of some substances at 20°C
|
− |
Material |
Resistivity (Ω m) |
|
Conductors |
Silver |
1.60 × 10−8 |
|
Copper |
1.62 × 10−8 |
|
|
Aluminium |
2.63 × 10−8 |
|
|
Tungsten |
5.20 × 10−8 |
|
|
Nickel |
6.84 × 10−8 |
|
|
Iron |
10.0 × 10−8 |
|
|
Chromium |
12.9 × 10−8 |
|
|
Mercury |
94.0 × 10−8 |
|
|
Manganese |
1.84 × 10−6 |
|
|
Constantan (alloy of Cu and Ni) |
49 × 10−6 |
|
|
Alloys |
Manganin (alloy of Cu, Mn and Ni) |
44 × 10−6 |
|
Nichrome (alloy of Ni, Cr, Mn and Fe) |
100 × 10−6 |
|
|
Glass |
1010 − 1014 |
|
|
Insulators |
Hard rubber |
1013 − 1016 |
|
Ebonite |
1015 − 1017 |
|
|
Diamond |
1012 − 1013 |
|
|
Paper (dry) |
1012 |
(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?
a) Resistivity of iron =
Resistivity of mercury =
Resistivity of mercury is more than that of iron. This implies that iron is a better conductor than mercury.
(b) It can be observed from Table 12.2 that the resistivity of silver is the lowest among the listed materials. Hence, it is the best conductor.
Chap 12 - Electricity - P213 - Q1
Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5 Ω resistor, an 8 Ω resistor, and a 12 Ω resistor, and a plug key, all connected in series.
Three cells of potential 2 V, each prescribed in series, is equivalent to a battery of potential 2 V + 2 V + 2 V = 6V.
The following circuit diagram shows three resistors of resistances 5 Ω, 8 Ω and 12 Ω respectively connected in series and a battery of potential 6 V.
Chap 12 - Electricity - P213 - Q2
Redraw the circuit of question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure potential difference across the 12 Ω resistor. What would be the readings in the ammeter and the voltmeter?
To calculate the current flowing through the resistors, an ammeter should be connected in the circuit in series with the resistors. To measure the potential difference across the 12 Ω resistor, a voltmeter should be connected parallel to this resistor, as shown in the following figure.
The resistances are connected in series.
Ohm’s law can be used to obtain the readings of ammeter and voltmeter. According to Ohm’s law,
V = IR,
Where,
Potential difference, V = 6 V
Current flowing through the circuit/resistors = I
Resistance of the circuit, R =
= 0.24 A
Potential difference across 12 Ω resistor =
Current flowing through the 12 Ω resistor, I = 0.24 A
Therefore, using Ohm’s law, we obtain
Therefore, the reading of the ammeter will be 0.24 A.
The reading of the voltmeter will be 2.88 V.
Chap 12 - Electricity - P216 - Q1
Judge the equivalent resistance when the following are connected in parallel − (a) 16Ω and 106Ω, (b) 16Ω and 103Ω and 106Ω.
(a) When 1 Ω and 106 Ω are connected in parallel:
Let R be the equivalent resistance.
Therefore, equivalent resistance 1 Ω
(b) When 1 Ω, , and
are connected in parallel:
Let R be the equivalent resistance.
Therefore, equivalent resistance = 0.999 Ω
Chap 12 - Electricity - P216 - Q2
An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?
Resistance of electric lamp,
Resistance of toaster,
Resistance of water filter,
Voltage of the source, V = 220 V
These are connected in parallel, as shown in the following figure.
Let R be the equivalent resistance of the circuit.
According to Ohm’s law,
V = IR
Where,
Current flowing through the circuit = I
7.04 A of current is drawn by all the three given appliances.
Therefore, current drawn by an electric iron connected to the same source of potential 220 V = 7.04 A
Let be the resistance of the electric iron. According to Ohm’s law,
Therefore, the resistance of the electric iron is and the current flowing through it is 7.04 A.
Chap 12 - Electricity - P216 - Q3
What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?
The potential difference across each appliance is equal to the supplied voltage.
The total effective resistance of the circuit can be reduced by connecting electrical appliances in parallel
Chap 12 - Electricity - P216 - Q4
How can three resistors of resistances 2 Ω, 3 Ω and 6 Ω be connected to give a total resistance of (a) 4 Ω, (b) 1 Ω?
There are three resistors of resistances 2 Ω, 3 Ω, and 6 Ω respectively.
(a) The following circuit diagram shows the connection of the three resistors.
Here, 6 Ω and 3 Ω resistors are connected in parallel.
Therefore, their equivalent resistance will be given by
This equivalent resistor of resistance 2 Ω is connected to a 2 Ω resistor in series.
Therefore, equivalent resistance of the circuit = 2 Ω + 2 Ω =
Hence, the total resistance of the circuit is .
2. The following circuit diagram shows the connection of the three resistors.
All the resistors are connected in series. Therefore, their equivalent resistance will be given as
Therefore, the total resistance of the circuit is .
Chap 12 - Electricity - P216 - Q5
What is (a) the highest, (b) the lowest total resistance that can be secured by combinations of four coils of resistance 4 Ω, 8 Ω, 12 Ω, 24 Ω?
There are four coils of resistances , 12 Ω, and 24 Ω respectively.
(a) If these coils are connected in series, then the equivalent resistance will be the highest, given by the sum 4 + 8 + 12 + 24 =
(b) If these coils are connected in parallel, then the equivalent resistance will be the lowest, given by
Therefore, 2 Ω is the lowest total resistance
Chap 12 - Electricity - P218 - Q1
Why does the cord of an electric heater not glow while the heating element does?
Because of the amount of heat produced by it is proportional to its resistance. The resistance of the element of an electric heater is very high
Chap 12 - Electricity - P218 - Q2
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
The amount of heat (H) produced is given by the Joule’s law of heating as
Where,
Voltage, V = 50 V
Time, t = 1 h = 1 × 60 × 60 s
Amount of current,
Therefore, the heat generated is .
Chap 12 - Electricity - P218 - Q3
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
The amount of heat (H) produced is given by the joule’s law of heating as
Where,
Current, I = 5 A
Time, t = 30 s
Voltage, V = Current × Resistance = 5 × 20 = 100 V
Therefore, the amount of heat developed in the electric iron is
Chap 12 - Electricity - P220 - Q1
What determines the rate at which energy is delivered by a current?
The rate of consumption of electric energy in an electric appliance is called electric power
Chap 12 - Electricity - P220 - Q2
An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.
Power (P) is given by the expression,
Where,
Voltage, V = 220 V
Current, I = 5 A
Energy consumed by the motor = Pt
Where,
Time, t = 2 h = 2 × 60 × 60 = 7200 s
P = 1100 × 7200 = 7.92 × 106 J
Therefore, power of the motor = 1100 W
Energy consumed by the motor = 7.92 × 106 J
Chap 12 - Electricity - P221 - Q1
A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the ratio R/R' is −
(d) Resistance of a piece of wire is proportional to its length. A piece of wire has a resistance R. The wire is cut into five equal parts.
Therefore, resistance of each part =
All the five parts are connected in parallel. Hence, equivalent resistance (R’) is given as
Therefore, the ratio is 25.
Chap 12 - Electricity - P221 - Q2
Which of the following terms does not represent electrical power in a circuit?
(a) I2R
(b) IR2
(c) VI
(d) v2/r
(b) IR2
Chap 12 - Electricity - P221 - Q3
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be −
(d) 25 W
Chap 12 - Electricity - P221 - Q4
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be −
(a) 1:2
(b) 2:1
(c) 1:4
(d) 4:1
(c) 1:4
Chap 12 - Electricity - P221 - Q5
How is a voltmeter connected in the circuit to measure the potential difference between two points?
A voltmeter should be connected in parallel to the points
Chap 12 - Electricity - P221 - Q6
A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10−8 Ω m. What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?
Resistance (R) of a copper wire of length l and cross-section A is given by the expression,
Where,
Resistivity of copper,
Area of cross-section of the wire, A =
Diameter= 0.5 mm = 0.0005 m
Resistance, R = 10 Ω
Hence, length of the wire,
If the diameter of the wire is doubled, new diameter
Therefore, resistance
Therefore, the length of the wire is 122.7 m and the new resistance is
Chap 12 - Electricity - P221 - Q7
The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below −
The slope of the line gives the value of resistance (R) as,
Therefore, the resistance of the resistor is .
Chap 12 - Electricity - P221 - Q8
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Resistance (R) of a resistor is given by Ohm’s law as,
Where,
Potential difference, V = 12 V
Current in the circuit, I = 2.5 mA =
Therefore, the resistance of the resistor is
Chap 12 - Electricity - P221 - Q9
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?
There is no current division occurring in a series circuit. Current flow through the component is the same, given by Ohm’s law as
Where,
R is the equivalent resistance of resistances .
0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω, and12 Ω These are connected in series. Hence, the sum of the resistances will give the value of R.
R = 0.2 + 0.3 + 0.4 + 0.5 + 12 = 13.4 Ω
Potential difference, V = 9 V
Therefore, the current that would flow through the 12 Ω resistor is 0.671 A.
Chap 12 - Electricity - P221 - Q10
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
For x number of resistors of resistance 176 Ω, the equivalent resistance of the resistors connected in parallel is given by Ohm’s law as
Where,
Supply voltage, V = 220 V
Current, I = 5 A
Equivalent resistance of the combination = R,given as
From Ohm’s law,
Therefore, four resistors of 176 Ω are required to draw the given amount of current
Chap 12 - Electricity - P221 - Q11
Show how you would connect three resistors, each of resistance 6 Ω, so that the combination has a resistance of (i) 9 Ω, (ii) 4 Ω.
If we joints the resistors in series, then the equivalent resistance will be the sum of the resistors, i.e., 6 Ω + 6 Ω + 6 Ω = 18 Ω, which is not desired. If we connect the resistors in parallel, then the equivalent resistance will be
Hence, we should either connect the two resistors in series or parallel.
(i) Two resistors in parallel
Two 6 Ω resistors are connected in parallel. Their equivalent resistance will be
The third 6 Ω resistor is in series with 3 Ω. Hence, the equivalent resistance of the circuit is 6 Ω + 3 Ω = 9 Ω.
(ii) Two resistors in series
Two 6 Ω resistors are in series. Their equivalent resistance will be the sum
The third 6 Ω resistor is in parallel with 12 Ω. Hence, equivalent resistance will be
Therefore, the total resistance is .
Chap 12 - Electricity - P221 - Q12
Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W. How many lamps can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A?
Resistance R1 of the bulb is given by the expression,
Where,
Supply voltage, V = 220 V
Maximum allowable current, I = 5 A
Rating of an electric bulb
According to Ohm’s law,
V = I R
Where,
R is the total resistance of the circuit for x number of electric bulbs
Resistance of each electric bulb,
Therefore, 110 electric bulbs are connected in parallel
Chap 12 - Electricity - P221 - Q13
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?
Supply voltage, V = 220 V
Resistance of one coil, R =
(i) Coils are used separately
According to Ohm’s law,
Where,
is the current flowing through the coil
Therefore, 9.16 A current will flow through the coil when used separately.
(ii) Coils are connected in series
Total resistance,
According to Ohm’s law,
Where,
is the current flowing through the series circuit
Therefore, 4.58 A current will flow through the circuit when the coils are connected in series.
(iii) Coils are connected in parallel
Total resistance, is given as
According to Ohm’s law,
Where,
is the current flowing through the circuit
Therefore, 18.33 A current will flow through the circuit when coils are connected in parallel.
Chap 12 - Electricity - P221 - Q14
Compare the power used in the 2 Ω resistor in each of the following circuits: (i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and (ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
(i) Potential difference, V = 6 V
1 Ω and 2 Ω resistors are connected in series. Therefore, equivalent resistance of the circuit, R = 1 + 2 = 3 Ω
According to Ohm’s law,
V = IR
Where,
I is the current through the circuit
This current will flow through each component of the circuit because there is no division of current in series circuits. Hence, current flowing through the 2 Ω resistor is . Power is given by the expression,
(ii) Potential difference, V = 4 V
12 Ω and 2 Ω resistors are connected in parallel. The voltage across each component of a parallel circuit remains the same. Hence, the voltage across 2 Ω resistor will be 4 V.
Power consumed by 2 Ω resistor is given by
Therefore, the power used by 2 Ω resistor is 8 W.
Chap 12 - Electricity - P222 - Q15
Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
Both the bulbs are connected in parallel. Therefore, potential difference across each of them will be 220 V, because no division of voltage occurs in a parallel circuit.
Current drawn by the bulb of rating 100 W is given by,
Similarly, current drawn by the bulb of rating 100 W is given by,
Chap 12 - Electricity - P222 - Q16
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
Energy consumed by an electrical appliance is given by the expression,
Where,
Power of the appliance = P
Time = t
Energy consumed by a TV set of power 250 W in 1 h = 250 × 3600 = 9 × 105 J
Energy consumed by a toaster of power 1200 W in 10 minutes = 1200 × 600
= 7.2× 105 J
Therefore, the energy consumed by a 250 W TV set in 1 h is more than the energy consumed by a toaster of power 1200 W in 10 minutes.
Chap 12 - Electricity - P222 - Q17
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Rate of heat produced by a device is given by the expression for power as
Where,
Resistance of the electric heater, R = 8 Ω
Current drawn, I = 15 A
Therefore, heat is produced by the heater at the rate of 1800 J/s.
Chap 12 - Electricity - P222 - Q18
Explain the following.
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?
(a) The melting point of tungsten are very high. It does not burn readily at a high temperature. The electric lamps glow at very high temperatures. Hence, tungsten is mainly used as heating element of electric bulbs.
(b) The conductors of electric heating devices such as bread toasters and electric irons are made of alloy because resistivity of an alloy is more than that of metals. It produces large amount of heat.
(c) A component of a series circuit receives a small voltage for a large supply voltage. As a result, the amount of current decreases and the device becomes hot. Hence, series arrangement is not used in domestic circuits.
(d) Resistance (R) of a wire is inversely proportional to its area of cross-section (A), i.e.,
(e) Copper and aluminium wires have low resistivity. They are good conductors of electricity.
Chap 13 - Magnetic Effects of Electric Current
Chap 13 - Magnetic Effects of Electric Current - P224 - Q1
Why does a compass needle get deflected when brought near a bar magnet?
A compass needle shows a deflection when brought near the bar magnet, because a compass needle is a small bar magnet. When it is brought near a bar magnet, its magnetic field lines interact with that of the bar magnet.
Chap 13 - Magnetic Effects of Electric Current - P228 - Q1
Draw magnetic field lines around a bar magnet.
Chap 13 - Magnetic Effects of Electric Current - P228 - Q2
List the properties of magnetic lines of force.
The properties of magnetic lines of force are as follows.
(a) Magnetic field lines emerge from the north pole.
(b) They merge at the south pole.
(c) The direction of field lines inside the magnet is from the south pole to the north pole.
(d) Magnetic lines do not intersect with each other.
Chap 13 - Magnetic Effects of Electric Current - P228 - Q3
Why don’t two magnetic lines of force intersect each other?
If two field lines of a magnet intersect, then at the point of intersection, the compass needle points in two different directions. This is not possible. Hence, two field lines do not intersect each other.
Chap 13 - Magnetic Effects of Electric Current - P229 - Q1
Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.
For downward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop. Similarly, for upward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop,
Chap 13 - Magnetic Effects of Electric Current - P229 - Q2
The magnetic field in a given region is uniform. Draw a diagram to represent it.
Chap 13 - Magnetic Effects of Electric Current - P230 - Q3
Choose the correct option.
The magnetic field inside a long straight solenoid-carrying current
(a) is zero
(b) decreases as we move towards its end
(c) increases as we move towards its end
(d) is the same at all points
(d)The magnetic field inside a long, straight, current-carrying solenoid is uniform. It is the same at all points inside the solenoid.
Chap 13 - Magnetic Effects of Electric Current - P231 - Q1
Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)
(a) mass
(b) speed
(c) velocity
(d) momentum
(c) and (d)
Chap 13 - Magnetic Effects of Electric Current - P232 - Q2
In Activity 13.7 (page: 230), how do we think the displacement of rod AB will be affected if (i) current in rod AB is increased: (ii) a stronger horse-shoe magnet is used: and (iii) length of the rod AB is increased?
A current-carrying conductor placed in a magnetic field experiences a force. The magnitude of force increases with the amount of current, strength of the magnetic field, and the length of the conductor. Hence, the magnetic force exerted on rod AB and its deflection will increase if
(i) current in rod AB is increased
(ii) a stronger horse-shoe magnet is used
(iii) length of rod AB is increased
Working...
Chap 13 - Magnetic Effects of Electric Current - P232 - Q3
A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is
(a) towards south (b) towards east
(c) downward (d) upward
(d) upward
Chap 13 - Magnetic Effects of Electric Current - P233 - Q1
State Fleming’s left-hand rule.
Fleming’s left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the direction of magnetic field.
Chap 13 - Magnetic Effects of Electric Current - P233 - Q2
What is the principle of an electric motor?
A current-carrying loop experiences a force and rotates when placed in a magnetic field. The direction of rotation of the loop is given by the Fleming’s left-hand rule.
Chap 13 - Magnetic Effects of Electric Current - P233 - Q3
What is the role of the split ring in an electric motor?
The commutator reverses the direction of current flowing through the coil after each half rotation of the coil. Due to this reversal of the current, the coil continues to rotate in the same direction.
Chap 13 - Magnetic Effects of Electric Current - P236 - Q1
Explain different ways to induce current in a coil.
The different ways to induce current in a coil are as follows:
(a) If a coil is moved rapidly between the two poles of a horse-shoe magnet, then an electric current is induced in the coil.
(b) If a magnet is moved relative to a coil, then an electric current is induced in the coil.
Chap 13 - Magnetic Effects of Electric Current - P237 - Q1
State the principle of an electric generator.
An electric generator works on the principle of electromagnetic induction. It generates electricity by rotating a coil in a magnetic field.
Chap 13 - Magnetic Effects of Electric Current - P237 - Q2
Name some sources of direct current.
Some sources of direct current are cell, DC generator, etc.
Chap 13 - Magnetic Effects of Electric Current - P237 - Q3
Which sources produce alternating current?
AC generators, power plants, etc., produce alternating current.
Chap 13 - Magnetic Effects of Electric Current - P237 - Q4
Choose the correct option.
A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each
(a) two revolutions
(b) one revolution
(c) half revolution
(d) one-fourth revolution
(c) half revolution
Chap 13 - Magnetic Effects of Electric Current - P238 - Q1
Name two safety measures commonly used in electric circuits and appliances.
Two safety measures commonly used in electric circuits and appliances are as follows:
(i) When the current passing through the wire exceeds the maximum limit of the fuse element, the fuse melts to stop the flow of current through that circuit, hence protecting the appliances connected to the circuit.
(ii) Any leakage of current in an electric appliance is transferred to the ground and people using the appliance do not get the shock.
Chap 13 - Magnetic Effects of Electric Current - P238 - Q2
An electric oven of 2 kW is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.
Current drawn by the electric oven can be obtained by the expression,
P = VI
Where,
Current = I
Power of the oven, P = 2 kW = 2000 W
Voltage supplied, V = 220 V
Hence, the current drawn by the electric oven is 9.09 A, which exceeds the safe limit of the circuit. Fuse element of the electric fuse will melt and break the circuit.
Chap 13 - Magnetic Effects of Electric Current - P238 - Q3
What precaution should be taken to avoid the overloading of domestic electric circuits?
The precautions that should be taken to avoid the overloading of domestic circuits are as follows:
(a) Faulty appliances should not be connected in the circuit.
(b) Fuse should be connected in the circuit.
Chap 13 - Magnetic Effects of Electric Current - P240 - Q1
Which of the following correctly describes the magnetic field near a long straight wire?
(a) The field consists of straight lines perpendicular to the wire
(b) The field consists of straight lines parallel to the wire
(c) The field consists of radial lines originating from the wire
(d) The field consists of concentric circles centred on the wire
(d) The field consists of concentric circles centred on the wire
Chap 13 - Magnetic Effects of Electric Current - P240 - Q2
The phenomenon of electromagnetic induction is
(a) the process of charging a body
(b) the process of generating magnetic field due to a current passing through a coil
(c) producing induced current in a coil due to relative motion between a magnet and the coil
(d) the process of rotating a coil of an electric motor
(c) producing induced current in a coil due to relative motion between a magnet and the coil
Chap 13 - Magnetic Effects of Electric Current - P240 - Q3
The device used for producing electric current is called a
(a) generator
(b) galvanometer
(c) ammeter
(d) motor
(a) generator
Chap 13 - Magnetic Effects of Electric Current - P240 - Q4
The essential difference between an AC generator and a DC generator is that
(a) AC generator has an electromagnet while a DC generator has permanent magnet.
(b) DC generator will generate a higher voltage.
(c) AC generator will generate a higher voltage.
(d) AC generator has slip rings while the DC generator has a commutator.
(d) AC generator has slip rings while the DC generator has a commutator.
Chap 13 - Magnetic Effects of Electric Current - P240 - Q5
At the time of short circuit, the current in the circuit
(a) reduces substantially
(b) does not change
(c) increases heavily
(d) vary continuously
(c) increases heavily
Chap 13 - Magnetic Effects of Electric Current - P240 - Q6
State whether the following statements are true or false.
(a) An electric motor converts mechanical energy into electrical energy.
(b) An electric generator works on the principle of electromagnetic induction.
(c) The field at the centre of a long circular coil carrying current will be parallel straight lines.
(d) A wire with a green insulation is usually the live wire of an electric supply.
(a) False
(b) True
(c) True
(d) False
Chap 13 - Magnetic Effects of Electric Current - P240 - Q7
List three sources of magnetic fields.
Three sources of magnetic fields are as follows:
(a) Current-carrying conductors
(b) Permanent magnets
(c) Electromagnets
Chap 13 - Magnetic Effects of Electric Current - P241 - Q8
How does a solenoid behave like a magnet? Can you determine the north and south poles of a current-carrying solenoid with the help of a bar magnet? Explain.
In the above figure, when the north pole of a bar magnet is brought near the end connected to the negative terminal of the battery, the solenoid repels the bar magnet. Since like poles repel each other, the end connected to the negative terminal of the battery behaves as the north pole of the solenoid and the other end behaves as a south pole. Hence, one end of the solenoid behaves as a north pole and the other end behaves as a south pole.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q9
When is the force experienced by a current-carrying conductor placed in a magnetic field largest?
when the direction of current is perpendicular to the direction of the magnetic field.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q10
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?
The direction of current is from the front wall to the back wall because negatively charged electrons are moving from back wall to the front wall. The direction of magnetic force is rightward. Hence, using Fleming’s left hand rule, it can be concluded that the direction of magnetic field inside the chamber is downward.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q11
Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor?
When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotating anti-clockwise. This happens because a downward force acts on length MN and at the same time, an upward force acts on length ST. As a result, the coil rotates anti-clockwise.
Current in the length MN flows from M to N and the magnetic field acts from left to right, normal to length MN. Therefore, according to Fleming’s left hand rule, a downward force acts on the length MN. Similarly, current in the length ST flows from S to T and the magnetic field acts from left to right, normal to the flow of current. Therefore, an upward force acts on the length ST. These two forces cause the coil to rotate anti-clockwise.
After half a rotation, the position of MN and ST interchange. The half-ring D comes in contact with brush A and half-ring C comes in contact with brush B. Hence, the direction of current in the coil MNST gets reversed.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q12
Name some devices in which electric motors are used?
Some devices in which electric motors are used are as follows:
(a) Water pumps
(b) Electric fans
(c) Electric mixers
(d) Washing machines
Chap 13 - Magnetic Effects of Electric Current - P241 - Q13
A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?
A current induces in a solenoid if a bar magnet is moved relative to it. This is the principle of electromagnetic induction.
(i) A current is induced momentarily in the coil. As a result, the needle of the galvanometer deflects momentarily in a particular direction.
(ii) The needle of the galvanometer deflects momentarily in the opposite direction.
(iii) galvanometer will show no deflection.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q14
Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.
Two circular coils A and B are placed close to each other. When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. This is called electromagnetic induction.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q15
State the rule to determine the direction of a (i) magnetic field produced around a straight conductor-carrying current, (ii) force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it, and (iii) current induced in a coil due to its rotation in a magnetic field.
(i) Maxwell’s right hand thumb rule
(ii) Fleming’s left hand rule
(iii) Fleming’s right hand rule
Chap 13 - Magnetic Effects of Electric Current - P241 - Q16
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
An electric generator converts mechanical energy into electrical energy.
The principle of working of an electric generator is that when a loop is moved in a magnetic field, an electric current is induced in the coil. It generates electricity by rotating a coil in a magnetic field. The following figure shows a simple AC generator.
The direction of current in the coil is MNST. Hence, the galvanometer shows a deflection in a particular direction. After half a rotation, length MN starts moving down whereas length ST starts moving upward. The direction of the induced current in the coil gets reversed as TSNM. As the direction of current gets reversed after each half rotation, the produced current is called an alternating current (AC).
To get a unidirectional current, instead of two slip rings, two split rings are used, as shown in the following figure.
In this arrangement, brush A always remains in contact with the length of the coil that is moving up whereas brush B always remains in contact with the length that is moving down. The split rings C and D act as a commutator.
The direction of current induced in the coil will be MNST for the first rotation and TSNM in the second half of the rotation. Hence, a unidirectional current is produced from the generator called DC generator. The current is called AC current.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q17
When does an electric short circuit occur?
When the insulation of live and neutral wires undergoes wear and tear and then touches each other, the current flowing in the circuit increases abruptly. Hence, a short circuit occurs.
Chap 13 - Magnetic Effects of Electric Current - P241 - Q18
What is the function of an earth wire? Why is it necessary to earth metallic appliances?
earth wire so that any leakage of electric current is transferred to the ground. This prevents any electric shock to the user. That is why earthing of the electrical appliances is necessary.
Chap 14 - Sources of Energy
Chap 14 - Sources of Energy - P243 - Q1
What is a good source of energy?
In our daily lives, use energy from various sources for doing work. We use diesel to run our trains. We use electricity to light our street-lamps. Or we use energy in our muscles to cycle to school.
Chap 14 - Sources of Energy - P243 - Q2
What is a good fuel?
A good fuel produces a huge amount of heat on burning, does not produce a lot of smoke, and is easily available.
Chap 14 - Sources of Energy - P243 - Q3
What is a good fuel?
It is a huge amount of heat on burning, does not produce a lot of smoke, and is easily available.
Chap 14 - Sources of Energy - P248 - Q1
What are the disadvantages of fossil fuels?
1. air pollution caused by burning of coal or petroleum products.
2. The oxides of carbon, nitrogen and sulphur that are released on burning
fossil fuels are acidic oxides. These lead to acid rain which affects our
water and soil resources.
Chap 14 - Sources of Energy - P248 - Q2
Why are we looking at alternate sources of energy?
Because Fossil fuels, which have been traditionally used by human beings as an energy sources, are non-renewable sources of energy. These sources of energy are limited and cannot replenish on their own. They are being consumed at a large rate. If this rate of consumption continues, then the fossil fuels would be exhausted from the Earth.
Chap 14 - Sources of Energy - P248 - Q3
How has the traditional use of wind and water energy been modified for our convenience?
Traditionally, waterfalls were used as a source of Storage body which was converted to electricity with the help of turbines. Since waterfalls are few in number, water dams have been constructed in large numbers. Nowadays, hydro-dams are used in order to harness potential energy of stored water. In water dams, water falls from a height on the turbine, which produces electricity.
Earlier, the windmills were used to harness wind energy to do mechanical work such as lifting/drawing water from a well. Today, windmills are used to generate electricity. In windmills, the kinetic energy of wind is harnessed and converted into electricity. The rotatory motion of the blades turns the turbine of the electric generator to generate electricity.
Chap 14 - Sources of Energy - P253 - Q1
What kind of mirror − concave, convex or plain − would be best suited for use in a solar cooker? Why
A solar cooker uses heat of the sunlight to cook and heat food. A mirror is used in order to reflect and focus sunlight at a point.
A concave mirror is used in a solar cooker for this purpose. The mirror focuses all the incident sunlight at a point. The temperature at that point increases, thereby cooking and heating the food placed at that point.
Chap 14 - Sources of Energy - P253 - Q1
Can any source of energy be pollution-free? Why or why not?
No source of energy can be pollution-free. Because To start the fusion reactions, approximately 107 K temperature is required, which is provided by fission reactions. The wastes released from fission reactions are very hazardous. Hence, no source of energy is pollution-free.
Chap 14 - Sources of Energy - P253 - Q2
What are the limitations of the energy that can be obtained from the oceans?
Tidal energy depends on the relative positioning of the Earth, moon, and the Sun.
(ii) High dams are required to be built to convert tidal energy into electricity.
(iii) Very strong waves are required to obtain electricity from wave energy.
(iv) To harness ocean thermal energy efficiently, the difference in the temperature of surface water (hot) and the water at depth (cold) must be 20ºC or more.
Chap 14 - Sources of Energy - P253 - Q2
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Hydrogengas is cleaner than CNG. CNG contains hydrocarbons. Therefore, it has carbon contents. Because fusion of hydrogen does not produce any waste.
Chap 14 - Sources of Energy - P253 - Q3
What is geothermal energy?
When underground water comes in contact with the hot spot, steam is generated. Sometimes hot water from that region finds outlets
at the surface. Such outlets are known as hot springs. The steam trapped in rocks is routed through a pipe to a turbine and used to generate electricity. The cost of production would not be much, but there are very few commercially viable sites where such energy can be exploited.
Chap 14 - Sources of Energy - P253 - Q4
What are the advantages of nuclear energy?
(a) Fusion of four hydrogen atoms produces huge amount of energy approximately equal to 27 MeV.
(b) Large amount of energy is produced per unit mass. Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon.
Chap 14 - Sources of Energy - P254 - Q1
Name two energy sources that you would consider to be renewable. Give reasons for your choices.
Bio-Mass
cow-dung, various plant materials like the residue afterharvesting the crops, vegetable waste and sewage are decomposed in
the absence of oxygen to give bio-gas. Since the starting material is mainlycow-dung, it is popularly known as ‘ gobar-gas’.
Wind
To generate electricity, the rotatory motion of the windmill is used to turn the turbine of the electric generator. The output of a single windmill is quite small and cannot be used for commercial purposes. Therefore, a number of windmills are erected over a large area, which is known as wind energyfarm.
Chap 14 - Sources of Energy - P254 - Q1
A solar water heater cannot be used to get hot water on
(a) a sunny day (b) a cloudy day
(c) a hot day (d)a windy day
(b) a cloudy day
Chap 14 - Sources of Energy - P254 - Q2
Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.
Two exhaustible energy sources are as follows:
(a) Coal: It is produced from dead remains of plants and animals that remain buried under the earth’s crust for millions of years. It takes millions of years to produce coal. Industrialization has increased the demand of coal. However, coal cannot replenish within a short period of time. Hence, it is a non-renewable or exhaustible source of energy.
(b) Wood: It is obtained from forests. Deforestation at a faster rate has caused a reduction in the number of forests on the Earth. It takes hundreds of years to grow a forest. If deforestation is continued at this rate, then there would be no wood left on the Earth. Hence, wood is an exhaustible source of energy.
Chap 14 - Sources of Energy - P255 - Q2
Which of the following is not an example of a bio-mass energy source?
(a) wood
(b) gobar gas
(c) nuclear energy
(d) coal
(c) nuclear energy
Chap 14 - Sources of Energy - P255 - Q3
Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy?
(a) Geothermal energy
(b) Wind energy
(c) Nuclear energy
(d) Bio-mass
(c) Nuclear energy
Chap 14 - Sources of Energy - P255 - Q4
Compare and contrast fossil fuels and the Sun as direct sources of energy.
Fossil fuels are energy sources, such as coal and petroleum, obtained from underneath the Earth’s crust. They are directly available to human beings for use.
On the other hand, solar energy is a renewable and direct source of energy.Solar energy is available free of cost to all in unlimited amount. It replenishes in the Sun itself
Chap 14 - Sources of Energy - P255 - Q5
Compare and contrast bio-mass and hydro electricity as sources of energy.
Hydro-electricity, on the other hand, is obtained from the potential energy stored in water at a height. Energy from it can be produced again and again. It is harnessed from water and obtained from mechanical processes.
Chap 14 - Sources of Energy - P255 - Q6
What are the limitations of extracting energy from −
(a) the wind? (b) waves? (c) tides?
(a) Wind energy is harnessed by windmills. One of the limitations of extracting energy from wind is that a windmill requires wind of speed more than 15 km/h to generate electricity. Also, a large number of windmills are required, which covers a huge area.
(b) Very strong ocean waves are required in order to extract energy from waves.
(c) Very high tides are required in order to extract energy from tides. Also, occurrence of tides depends on the relative positions of the Sun, moon, and the Earth.
Chap 14 - Sources of Energy - P255 - Q7
On what basis would you classify energy sources as
(a) renewable and non-renewable?
(b) exhaustible and inexhaustible?
Are the options given in (a) and (b) the same?
(a) The source of energy that replenishes in nature is known as renewable source of energy. Sun, wind, moving water, bio-mass, etc. are some of the examples of renewable sources of energy.
The source of energy that does not replenish in nature is known as non-renewable source of energy. Coal, petroleum, natural gas, etc. are some of the examples of non-renewable sources of energy.
(b) Exhaustible sources are those sources of energy, which will deplete and exhaust after a few hundred years. Coal, petroleum, etc. are the exhaustible sources of energy.
Inexhaustible resources of energy are those sources, which will not exhaust in future. These are unlimited. Bio-mass is one of the inexhaustible sources of energy.
Yes. The options given in (a) and (b) are the same.
Chap 14 - Sources of Energy - P255 - Q8
What are the qualities of an ideal source of energy?
An ideal source of energy must be:
I. Economical
II. Easily accessible
III. Smoke/pollution free
Chap 14 - Sources of Energy - P255 - Q9
What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?
Solar cooker uses Sun’s energy to heat and cook food. It is inexhaustible and clean renewable source of energy
Disadvantage of a solar cooker is that it is very expensive. It does not work without sunlight. Hence, on cloudy day, it becomes useless.
Chap 14 - Sources of Energy - P255 - Q10
What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?
It is not possible to completely reduce the consumption of fossil fuels. However, some measures can be taken such as using electrical appliances wisely and not wasting electricity. Unnecessary usage of water should be avoided. Public transport system with mass transit must be adopted on a large scale. These small steps may help in reducing the consumption of natural resources and conserving them.
Chap 15 - Our Environment
Chap 15 - Our Environment - P257 - Q1
Why are some substances biodegradable and some non-biodegradable?
substances such as metal, glass, plastic, etc. which cannot be decomposed by the living organisms are non-biodegradable wastes.
substances such as paper, vegetable wastes, etc. that can be easily broken down by enzymes are biodegradable wastes
Chap 15 - Our Environment - P257 - Q2
Give any two ways in which biodegradable substances would affect the environment.
Biodegradable substances affect the environment in the following ways:
(i) The biodegradable substances such as tree leaves, plant parts, and kitchen wastes can be used as humus after composting. T
(ii)These substances after decomposition release that carbon back into the atmosphere.
Chap 15 - Our Environment - P257 - Q3
Give any two ways in which non-biodegradable substances would affect the environment.
Non-biodegradable substances affect the environment in the following ways:
(i) They contaminate soil and water resources as they cannot be decomposed by micro-organisms.
(ii) when accidentally eaten by stray animals, can harm them and can even cause their death.
Chap 15 - Our Environment - P261 - Q1
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
A trophic level is the level of species in an ecosystem on the basis of the source of nutrition such as producers, primary consumers, secondary consumers, etc.
Various trophic levels are connected through food chains. For example, in an aquatic food chain, phytoplanktons are the producers, zooplanktons are the primary consumers, and small fish is the secondary consumer and so on.
Chap 15 - Our Environment - P261 - Q2
What is the role of decomposers in the ecosystem?
Decomposers include micro-organisms such as bacteria and fungi that obtain nutrients by breaking down the remains of dead plants and animals. The body of dead plants and animals into simple inorganic raw materials, such as CO2, H2O, and some nutrients.
Chap 15 - Our Environment - P264 - Q1
What is ozone and how does it affect any ecosystem?
The high energy UV radiations break down O2 molecules into nascent oxygen.
(Nascent Oxygen)
Then, this free oxygen atom combines with an oxygen molecule to form ozone.
In recent years, the amount of ozone in the atmosphere is getting depleted.
This ozone depletion causes a greater amount of ultra violet radiation to enter earth’s atmosphere. This has an indirect effect on the ecosystem.(Ecosystem includes both the biological community and the non-living components of an area). It results in the death of many phytoplanktons, thereby affecting the process of photosynthesis. Plants utilise atmospheric CO2 to make their food. In the absence of plants, the levels of CO2 in the atmosphere will increase, which would in turn lead to an increase in global warming.
Chap 15 - Our Environment - P264 - Q1
Which of the following groups contain only biodegradable items?
(a) Grass, flowers and leather
(b) Grass, wood and plastic
(c) Fruit-peels, cake and lime-juice
(d) Cake, wood and grass
(c)Fruit-peels, cake, and lime-juice
(d)Cake, wood, and grass
Chap 15 - Our Environment - P264 - Q2
Which of the following constitute a food-chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat
(b) Grass, goat, and human
Chap 15 - Our Environment - P264 - Q3
Which of the following are environment-friendly practices?
(a) Carrying cloth-bags to put purchases in while shopping
(b) Switching off unnecessary lights and fans
(c) Walking to school instead of getting your mother to drop you on her scooter
(d) All of the above
(d) All of the above
Chap 15 - Our Environment - P265 - Q4
What will happen if we kill all the organisms in one trophic level?
Various trophic levels are connected through the food chains. If all the organisms of any one trophic level are killed, then it will disrupt the entire food chain.
This is just an example of one food chain. However, in nature, food chains are not isolated. They are interconnected in the form of food web. Therefore, killing all the plants of an area will not only affect the deer, it will also affect other herbivores such as goat, cattle, sheep, etc.
Chap 15 - Our Environment - P265 - Q5
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Organisms of all trophic levels are equally important and are an integral part of the ecosystem.
Now let us suppose that all the deer (herbivores) are killed in a region. This can lead to an increase in the number of producers. At the same time, there will be an increase in the number of other herbivores such as rabbits, goat, sheep, etc. due to less competition. This will also lead to the increase in population of only consumers of these increased herbivores. Thus, the balance in the ecosystem gets disturbed if any of its component organisms are removed.
Chap 15 - Our Environment - P265 - Q6
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Biomagnification is the increase in the concentration of pollutants or harmful chemicals within each step of the food chain. DDT was sprayed and the producers were found to have 0.04 ppm concentration of DDT. Since many types of planktons are eaten by some fishes and clams, their body accumulates 0.23 ppm of DDT. Sea gull that feeds on clams accumulates more DDT as one sea gull eats many clams. Hawk, the top carnivore, has the highest concentration of DDT.
Chap 15 - Our Environment - P265 - Q7
What are the problems caused by the non-biodegradable wastes that we generate?
Non-biodegradable substances affect the environment in the following ways:
(i) Since the non-biodegradable substances cannot be broken down, they get accumulated and thus contaminate the soil and the water resources.
(ii) These substances, when accidentally eaten by some stray animal, can harm them and can even cause their death.
Chap 15 - Our Environment - P265 - Q8
If all the waste we generate is biodegradable, will this have no impact on the environment?
The problem associated with waste management and disposal will also not occur. The population of decomposers will increase to breakdown the extra biodegradable waste generated.
Chap 15 - Our Environment - P265 - Q9
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
Ozone depletion occurs widely in the stratosphere. However, it is more prominent over the Antarctic region and is known as the ozone hole
* It causes skin darkening, skin cancer, ageing, and corneal cataracts in human beings.
* It can result in the death of many phytoplanktons that leads to increased global warming.
Chap 16 - Management of Natural Resources
Chap 16 - Management of Natural Resources - P269 - Q1
What changes can you make in your habits to become more environment-friendly?
Because objects made of plastic do not get decomposed easily. Besides soil fertility, they badly affect our environment. We should dispose the wastes safely and not disperse in public places. These are a few things that can be done to become more environment- friendly.
Chap 16 - Management of Natural Resources - P269 - Q2
What would be the advantages of exploiting resources with short-term aims?
We should not exploit resources for our short term gains as this would only lead to depletion of natural resources for the present generation as well as generations to come. Hence, we can say that there are hardly any advantages of exploiting natural resources for short term gains.
Chap 16 - Management of Natural Resources - P269 - Q3
How would these advantages differ from the advantages of using a long-term perspective in managing our resources?
Management ensures uniform distribution among the people. It conserves the natural resources for many years and not just for a few years, as in the case of a short-term perspective in conserving natural resources.
Chap 16 - Management of Natural Resources - P269 - Q4
Why do you think there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Natural resources of the Earth must be distributed among the people uniformly so that each and every one gets his share of the resource.
Human greed, corruption, and the lobby of the rich and powerful are the forces working against an equitable distribution of resources.
Chap 16 - Management of Natural Resources - P273 - Q1
Why should we conserve forests and wildlife?
A large number of tribes are the habitants in and around the forests. If the forests are not conserved, then it may affect these habitants. Without proper management of forest and wildlife, the quality of soil, the water sources, and even the amount of rainfall may be affected. Without forest and wildlife, life would become impossible for human beings.
Chap 16 - Management of Natural Resources - P273 - Q2
Suggest some approaches towards the conservation of forests.
(a) People should show their participation in saving the forest by protesting against the cutting of trees. For example, Chipko Andolan
(b) Planting of trees should be increased. Rate of afforestation must be more than that of deforestation.
(c) Some people cut precious trees such as Chandan to earn money. Government should take legal steps to catch these wood smugglers.
Chap 16 - Management of Natural Resources - P276 - Q1
Find out about the traditional systems of water harvesting/management in your region.
One of the traditional systems of water harvesting used in our region is tanks.
Chap 16 - Management of Natural Resources - P276 - Q2
Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
In plains, the water harvesting structures are crescent-shaped earthen embankments. These are low, straight, and concrete.
In hilly regions, It involves a collection of rain water in a stream, which is then diverted into man-made channels down the hill sides.
Chap 16 - Management of Natural Resources - P276 - Q3
Find out the source of water in your region/locality. Is water from this source available to all people living in that area?
The source of water in our region is ground water. Water from the source is available to all the people living in that area.
Chap 16 - Management of Natural Resources - P278 - Q1
What changes would you suggest in your home in order to be environment-friendly?
Changes that can be undertaken in our homes to be environment-friendly are listed below:
(i)Throw biodegradable and non-biodegradable waste into separate bins.
(ii)Construct composting pits.
(iii)Food items such as jam, pickles, etc., come packed in plastic bottles. These bottles can later be used for storing things in the kitchen.
Chap 16 - Management of Natural Resources - P278 - Q2
Can you suggest some changes in your school which would make it environment-friendly?
Changes that can be undertaken in our schools to make it environment friendly are listed below:
(i) Turn the taps off when not in use.
(ii) Biodegradable and non-biodegradable wastes should be thrown into separate bins.
Working...
Chap 16 - Management of Natural Resources - P278 - Q3
We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?
Because the forest department is the care taker of the forest land and is responsible for any damage to the forest.
Chap 16 - Management of Natural Resources - P279 - Q4
How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?
(a) Forest and wildlife:
(i) We should protest against the poaching of wild animals.
(ii) We should stop the annexation of forest land for our use.
(b) Water resources:
(i) We should practice rainwater harvesting.
(ii) We should avoid the discharge of sewage and other wastes into rivers and other water resources.
(c) Coal and petroleum:
(i) We should stop using coal as a fuel (angithis).
(ii)We should use alternative sources of energy such as hydro-energy and solar energy instead of depending largely on coal and petroleum.
Working...
Chap 16 - Management of Natural Resources - P279 - Q5
What can you as an individual do to reduce your consumption of the various natural resources?
Natural resources such as water, forests, coal and petroleum, etc. are important for the survival of human beings. The ways in which we can reduce the consumption of various natural resources are as follows:
(i) We should practice rainwater harvesting.
(ii) We should practice car pooling to avoid the excessive use of petroleum.
(iii) We should use alternative sources of energy such as hydro-energy and solar energy.
Chap 16 - Management of Natural Resources - P279 - Q6
List five things you have done over the last one week to −
(a) conserve our natural resources
(b) increase the pressure on our natural resources
(a) To conserve our natural resources:
(i) Travel by a CNG bus for long distances and walk for short distances.
(ii) Use recycled paper
(iii) Throw biodegradable and non-biodegradable waste into separate bins
(iv) Plant trees
(v) Harvest rainwater
(b) To increase the pressure on our natural resources:
(i) Use non-renewable resources of energy
(ii) Waste water
(iii) Waste electricity
(iv) Use plastics and polythene bags for carrying goods
(v) Use escalators
Chap 16 - Management of Natural Resources - P279 - Q7
On the basis of the issues raised in this chapter, what changes would you incorporate in your life-style in a move towards a sustainable use of our resources?
One should incorporate the following changes in life-style in a move towards a sustainable use of our resources:
(i) Throw biodegradable and non-biodegradable waste into separate bins.
(ii) Waste minimum amount of water while using and repair leaking taps.
(iii) Practice rainwater harvesting.
(iv) Avoid using vehicles for short distances. Instead, one can walk or cycle to cover short distances. To cover long distances, one should take a bus instead of using personal vehicles.
(v) Switch off electrical appliances when not in use.
(vi) Use fluorescent tubes in place of bulbs to save electricity.
(vii) Take stairs and avoid using lifts.
(viii) During winters, wear an extra sweater to avoid using heaters.
CBSE 10TH Economics
Social Science - Economics - Syllabus 2010 - CBSE X
Class X
Theory Paper 1
3 Hours Marks 80 + 20
for internal assessment
Marks Periods
Unit 1 :India and the contemporary World - II 20 45
Unit 2 :India - Resources and their Development 18 40
Unit 3 :Democratic Politics II 18 40
Unit 4 :Understanding Economics - II 16 40
Unit 5 :Disaster Management 8 25
Internal Assessment
1. Tests (formative and summative) 10
2. Assignments (School & Home assignments) 05
3. Project work 05
Unit 1 : India and the Contemporary world - II
| Themes | Objectives |
| Students are required to choose any two themes each
from the first two sub units and one from the third sub-unit. In sub-unit 1.1, theme 3 is compulsory. For second theme in that subunit, students are required to choose any one from the first two themes. Thus all students are required to study five themes in all. Sub-unit 1.1 : Events and processes : 1. Nationalism in Europe : (a) The growth of nationalism in Europe after the 1830s. (b) The ideas of Giuseppe Mazzini etc. (c) General characteristics of the movements in Poland, Hungary, Italy, Germany and Greece. 2. Nationalist Movement in Indo China : Factors leading to growth of rationalism in India (a) French colonialism in Indochina. (b) Phases of struggle against the French. (c) The ideas of Phan Dinh Phung, Phan Boi Chau, Nguyen Ac Quoc (d) The second world war and the liberation struggle. (e) America and the second Indochina war. 3. Nationalism in India : Civil Disobedience Movement (a) First world war, Khilafat and Non-Cooperation. (b) Salt Satyagraha. (c) Movements of peasants, workers, tribals. (d) Activities of different political groups. Sub-unit 1.2 : Economies and livelihoods : 4. Industrialization 1850s - 1950s : (a) Contrast between the form of industrialization in Britain and India. (b) Relationship between handicrafts and industrial production, formal and informal sectors. (c) Livelihood of workers. Case studies : Britain and India. 5. Urbanization and urban lives : (a) Patterns of urbanization (b) Migration and the growth of towns. (c) Social change and urban life. (d) Merchants, middle classes, workers and urban poor. Case studies : London and Bombay in the nineteenth and twentieth century. 6. Trade and Globalization : (a) Expansion and integration of the world market in the nineteenth and early twentieth century. (b) Trade and economy between the two Wars. (c) Shifts after the 1950s. (d) Implications of globalization for livelihood patterns. Case study : The post War International Economic order, 1945 to 1960s. Sub-unit 1.3 : Culture, Identity and Society 7. Print culture and nationalism. (a) The history of print in Europe. (b) The growth of press in nineteenth century India. (c) Relationship between print culture, public debate and politics. 8. History of the novel: (a) Emergence of the novel as a genre in the west. (b) The relationship between the novel and changes in modern society. (c) Early novels in nineteenth century India. (d) A study of two or three major writers. Sub-unit 1.4 : Map Work (2 Marks) |
|
| Themes | Objectives |
| 1. Resources : Types - natural and human;
Need for resource planning. 2. Natural Resources : land as a resource, soil types and distribution; changing land use pattern; land degradation and conservation measures. 3. Forest and Wild life resources : types and distribution ,depletion of flora and fauna; conservation and protection of forest and wild life. 4. Agriculture : types of farming, major crops, cropping pattern, technological and institutional reforms; their impact; contribution of Agriculture to national economy - employment and output. 5. Water resources : sources, distribution, utilisation, multi-purpose projects, water scarcity, need for conservation and management, rainwater harvesting. (One case study to be introduced) 6. Mineral Resources : types of minerals, distribution, use and economic importance of minerals, conservation. 7. Power Resources : types of power resources : conventional and non-conventional, distribution and utilization, and conservation. 8. Manufacturing Industries : Types, spatial distribution, contribution of industries to the national economy, industrial pollution and degradation of environment, measures to control degradation. (One case study to be introduced) 9. Transport, communication and trade 10. Map Work (4 marks)
|
Understand the value of resources and the need for
their judicious utilisation and conservation; Identify various types of farming and discuss the various farming methods; To describe the spatial distribution of major crops as well as understand the relationship between rainfall regimes and cropping pattern; Explain various government policies for institutional as well as technological reforms since independence; Understand the importance of forest and wild life in our environment as well as develop concept towards depletion of resources. Understand the importance of agriculture in national economy; Understand the importance of water as a resource as well as develop awareness towards its judicious use and conservation; Discuss various types of minerals as well as their uneven nature of distribution and explain the need for their judicious utilisation; Discuss various types of conventional and nonconventional resources and their utilization Discuss the importance of industries in the national economy as well as understand the regional disparities which resulted due to concentration of industries in some areas; Discuss the need for a planned industrial development and debate over the role of government towards sustainable development; To explain the importance of transport and communication in the ever shrinking world; To understand the role of trade in the economic development of a country, |
Project / Activity
- Learners may collect photographs of typical rural houses, and clothing of people from different regions of
India and examine whether they reflect any relationship with climatic conditions and relief of the area.
- Learners may write a brief report on various irrigation practices in the village and the change in cropping
pattern in the last decade.
Posters
- Pollution of water in the locality.
- Depletion of forests and the greenhouse effect.
Note : Any similar activities may be taken up.
Unit 3 : Democratic Politics II
Themes Themes Objectives 1. Power sharing mechanisms in democracy Why and how is power shared in democracies?
How has federal division of power in India
helped national unity? To what extent has
decentralisation achieved this objective? How
does democracy accommodate different social
groups?
2. Working of Democracy
Are divisions inherent to the working of
democracy? What has been the effect of caste
on politics and of politics on caste? How has
the gender division shaped politics? How do
communal divisions affect democracy?
3. Competition and contestations in democracy
How do struggles shape democracy in favour
of ordinary people? What role do political
parties play in competition and contestation?
Which are the major national and regional parties
in India? Why have social movements come to
occupy large role in politics?
4. Outcomes of democracy
Can or should democracy be judged by its
outcomes? What outcomes can one reasonably
expect of democracies? Does democracy in
India meet these expectations? Has democracy
led to development, security and dignity for the
people? What sustains democracy in India?
5. Challenges to democracy
Is the idea of democracy shrinking? What are
the major challenges to democracy in India? How
can democracy be reformed and deepened?
What role can an ordinary citizen play in
deepening democracy?
- Analyse the relationship between social cleavages
and political competition with reference to Indian
situation.
- Understand and analyse the challenges posed by
communalism to Indian democracy.
- Understand the enabling and disabling effects of
caste and ethnicity in politics.
- Develop a gender perspective on politics.
- Introduce students to the centrality of power
sharing in a democracy.
- Understand the working of spatial and social
power sharing mechanisms.
- Analyse federal provisions and institutions.
- Understand the new Panchayati Raj institutions
in rural and urban areas.
- Understand the vital role of struggle in the
expansion of democracy.
- Analyse party systems in democracies.
- Introduction to major political parties in the
country.
- Analyse the role of social movements and nonparty
political formations
- Introduction to the difficult question of evaluating
the functioning of democracies
- Develop the skills of evaluating Indian democracy
on some key dimensions : development, security
and dignity for the people.
- Understand the causes for continuation of
democracy in India.
- Distinguish between sources of strength and
weaknesses of Indian democracy
- Reflect on the different kinds of measures
possible to deepen democracy
- Promote an active and participatory citizenship.
Unit 4 : Understanding Economics II
Themes Learning Objectives 1. The Story of Development : The traditional notion of development; National Income
and Per-capita Income. Growth of NI - critical
appraisal of existing development indicators (PCI,
IMR, SR and other income and health indicators)
The need for health and educational development;
Human Development Indicators (in simple and brief
as a holistic measure of development.
The approach to this theme : Use case study of three
states (Kerala, Punjab and Bihar) or take a few
countries (India, China, Sri Lanka and one developed
country)
2. The Role of Service Sector in Indian
Economy : What is service sector (through examples)
: Importance of Service Sector in generating
employment and income to the nation (with the help
of a few case studies); Growth of Service Sector in
India; India as a major service provider to the world;
The need for public investment ; The role of important
infrastructure, education and health
3. Money and Financial System : Role of
money in an economy : Historical origin; Formal and
Informal financial institutions for Savings and Credit
- General Introduction; Select one formal institution
such as a nationalized commercial bank and a few
informal institutions; Local money lenders, landlords,
self help groups, chit funds and private finance
companies.
4. Globalisation : What is Globalisation
(through some simple examples); How India is being
globalised and why ; Development Strategy prior to
1991. State Control of Industries : Textile goods as
an example for elaboration; Economic Reforms
1991; Strategies adoped in Reform measures (easing
of capital flows; migration, investment flows);
Different perspectives on globalisation and its impact
on different sectors; Political Impact of globalisation.
5. Consumer Awareness : How consumer is
exploited (one or two simple case studies) factors
causing exploitation of consumers; Rise of consumer
awareness; how a consumer should be in a market;
role of government in consumer protection
- Familiarisation of some macroeconomic
concepts.
- Sensitizing the child about the rationale for overall
human development in our country, which include
the rise of income, improvements in health and
education rather than income.
- It is necessary to raise question in minds of the
children whether the increase in income alone is
sufficient for a nation.
- How and why people should be healthy and
provided with education.
- Familiarize the concept of money as an economic
concept;
- Create awareness of the role of financial
institutions from the point of view of day-to-day
life.
- To make aware of a major employment
generating sector.
- Sensitise the learner of how and why governments
invest in such an important sector.
- Provide children with some idea about how a
particular economic phenomenon is influencing
their surroundings and day-to-day life.
- Making the child aware of his or her rights and
duties as a consumer;
- Familiarizing the legal measures available to
protect from being exploited in markets.
Suggested Activities
Theme 2 :
Visit to banks and money lenders / pawnbrokers and discuss various activities that you have observed in banks in the
classroom;
Participate in the meetings of self help groups, which engaged in micro credit schemes in the locality of learners and
observe issues discussed.
Theme 4 :
Provide many examples of service sector activities. Use numerical examples, charts and photographs.
Theme 5 : Collect logos of standards available for various goods and services. Visit a consumer court nearby and
discuss in the class the proceedings; Collect stories of consumer exploitation and grievances from news papers and
consumer courts.
Unit 5 : Disaster Management
25 Periods
Tsunami
- Analyse the relationship between social cleavages
- Safer Construction Practices.
- Survival Skills.
- Alternate Communication systems during disasters.
- Sharing Responsibility
Prescribed Textbooks :
1. India and the Contemporary World-II (History) - Published by NCERT
2. Contemporary India II (Geography) - Published by NCERT
3. Democratic Politics II (Political Science) - Published by NCERT
4. Understanding Economic Development II - Published by NCERT
5. Together Towards a Safer India - Part III, a textbook an Disaster Management - Published by CBSE.
CBSE 10th Economics - Chap 1 - Development
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 1
1. Development of a country can generally be determined by
(i) its per capita income
(ii) its average literacy level
(iii) health status of its people
(iv) all the above
Ans:-(i)
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 2
2. Which of the following neighboring countries has better performance in terms of human development than India?
(i) Bangladesh
(ii) Sri Lanka
(iii) Nepal
(iv) Pakistan
Ans(iii)
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 3
3. Assume there are four families in a country. The average per capita income of these families is Rs 5000. If the income of three families is Rs 4000, Rs 7000 and Rs 3000 respectively, what is the income of the fourth family?
(i) Rs 7500
(ii) Rs 3000
(iii) Rs 2000
(iv) Rs 6000
Ans:-(iv)
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 4
4. What is the main criterion used by the World Bank in classifying different countries? What are the limitations of this criterion, if any?
Ans:- criterion is used by the World Bank in classifying countries. Countries with per capita income of Rs 4,53,000 per annum and above in 2004, are called rich countries and those with per capita income of Rs 37,000 or less are called low-income countries. Health and education indicators are the limitations of this criterion.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 5
5. In what respects is the criterion used by the UNDP for measuring development different from the one used by the World Bank?
Ans:- Human Development Report published by UNDP compares countries based on the educational
levels of the people, their health status and per capita income. While criterion is used by the World Bank in
classifying countries. Countries with per capita income of Rs 4,53,000 per annum and above in 2004, are called rich countries and those with per capita income of Rs 37,000 or less are called low-income countries. Therefore , UNDP criterion is different from World Bank measuring development criterion.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 6
6. Why do we use averages? Are there any limitations to their use? Illustrate with your own examples related to development.
Ans:- ‘Averages’ are useful for comparison, while average is useful for comparison but it does not tell us
how this income is distributed. This is one of the common limitations to use it among people.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 7
7. Kerala, with lower per capita income has a better human development ranking than Punjab. Hence, per capita income is not a useful criterion at all and should not be used to compare states. Do you agree? Discuss.
Ans:- Human Development Report published by UNDP compares countries based on the educational
levels of the people, their health status and per capita income .And according to it Kerala has greater human development than Punjab While Kerala has low per capita than punjab. But we can not say that per capita income is not a useful criterion.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 8
8. Find out present sources of energy used by people in India. What could be possibilities fifty years from now?
Ans:-There are following sources of energy used by people are as –water, crude oil, etc. As we know that water is an example of renewable resources. These resources are replenished by nature as in the case of crops and plants. However, even these resources may be overused. For example, in the case of groundwater, if we use more than what is being replenished by rain then we would be overusing this resource .While Non-renewable resources are those which will get exhausted after years of use. We have a fixed stock on earth which cannot be replenished. We do discover new resources that we did not know of earlier. New sources in this way add to the stock.. CRUDE OIL THAT WE EXTRACT FROM THE EARTH IS A NONRENEWABLE RESOURCE. Not many years the stock of crude oil will last if people continue to extract it at the present rate. The reserves would last only 43 years more. This is for the world as a whole. However, different countries face different situations. Countries like India depend on importing oil from abroad because they do not have enough stocks of their own. If prices of oil increase this becomes a burden for everyone. There are countries like USA which have low reserves and hence want to secure oil through military or economic power.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 9
9. Why is the issue of sustainability important for development?
Ans:- This issue is no longer region or nation specific. Our future is linked together. Sustainability of development is comparatively a new area of knowledge in which scientists, economists, philosophers and other social scientists are working together. In general, the question of development or progress is perennial.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 10
10. “The Earth has enough resources to meet the needs of all but not enough to satisfy the greed of even one person”. How is this statement relevant to the discussion of development? Discuss.
Ans:-As we know that there are various types of resources present beneath the earth surface in which Groundwater is an example of renewable resources. These resources are replenished by nature as in the
case of crops and plants. But if we use more than what is being replenished by rain then we would be overusing this resource. Here crude oil that is extracted from the earth is a non renewable resource and we have a fixed stock on earth which cannot be replenished. So the fruitful development of any country will be affected by the overusing of these sources of energy.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 11
11. List a few examples of environmental degradation that you may have observed around you.
Ans:-1.Cutting of trees.2.Use of plastics.3.Dumping sewage into river.4.exhaling harmful gases along with smoke.
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 12
12. For each of the items given in Table 1.6, find out which country is at the top and which is at the bottom.
Ans:-Per capita income in US$-Max-Sri Lanka(4390),Min-Myanmar(1027).
Life expectancy at birth Max- Sri Lanka(74),Min- Myanmar(61).
Literacy rate for 15+ years population-Max-Sri Lanka(91), Min-Bangladesh(41).
Gross enrolment ratio for thee years-Max- Sri Lanka(69), Pakistan(35).
HDI rank in the world-Max- Nepal(138),Min- Sri Lanka(93).
CBSE 10th Economics - Chap 1 - Development - Page 17 - Q 13
13. The following table shows the proportion of undernourished adults in India. It is in based on a survey of various states for the year 2001. Look at the table and answer the following questions.
State Male Female
(%) (%)
Kerala 22 19
Karnataka 36 38
Madhya Pradesh 43 42
All States 37 36
(i) Compare the nutritional level of people in Kerala and Madhya Pradesh.
(ii) Can you guess why around 40 per cent of people in the country are undernourished even though it is argued that there is enough food in the country? Describe in your own words.
(i) Compare the nutritional level of people in Kerala and Madhya Pradesh.
Ans:- Nutritional level of people in Kerala is more than in Madhya Pradesh.
(ii) Can you guess why around 40 per cent of people in the country are undernourished even though it is argued that there is enough food in the country? Describe in your own words.
Ans: Per capita income of India is very low due to which 40% people in the country are in poverty line. So they cannot afford to buy nourishing food.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 35 - Q 1
1. Fill in the blanks using the correct option given in the bracket:
(i) Employment in the service sector ________ increased to the same extent
as production. (has / has not)
(ii) Workers in the ________ sector do not produce goods.
(tertiary / agricultural)
(iii) Most of the workers in the _________ sector enjoy job security.
(organised / unorganised)
(iv) A _________ proportion of labourers in India are working in the unorganised
sector. (large / small)
(v) Cotton is a ________ product and cloth is a _________ product.
[natural /manufactured]
(vi) The activities in primary, secondary and tertiary sectors are _________
[independent / interdependent]
(i) Employment in the service sector has increased to the same extent
as production.
(ii) Workers in the tertiary sector do not produce goods.
(iii) Most of the workers in the organised sector enjoy job security.
(iv) A large proportion of labourers in India are working in the unorganised sector.
(v) Cotton is a natural product and cloth is a manufactured product.
(vi) The activities in primary, secondary and tertiary sectors are interdependent
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 35 - Q 2
2. Choose the most appropriate answer.
(a) The sectors are classified into public and private sector on the basis of:
(i) employment conditions
(ii) the nature of economic activity
(iii) ownership of enterprises
(iv) number of workers employed in the enterprise
(b) Production of a commodity, mostly through the natural process, is an
activity in _ primary ________ sector.
(i) primary
(ii) secondary
(iii) tertiary
(iv) information technology
(c) GDP is the total value of _ all final goods and services ________ produced during a particular year.
(i) all goods and services
(ii) all final goods and services
(iii) all intermediate goods and services
(iv) all intermediate and final goods and services
(d) In terms of GDP the share of tertiary sector in 2003 is between 50 per cent to 60 per cent
_________
(i) between 20 per cent to 30 per cent
(ii) between 30 per cent to 40 per cent
(iii) between 50 per cent to 60 per cent
(iv) 70 per cent
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 3
3. Match the following:
Problems faced by farming sector Some possible measures
1. Unirrigated land (a) Setting up agro-based mills
2. Low prices for crops (b) Cooperative marketing societies
3. Debt burden (c) Procurement of food grains by government
4. No job in the off season (d) Construction of canals by the government
5. Compelled to sell their grains to (e) Banks to provide credit with low interest
the local traders soon after harvest
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 4
4. Find the odd one out and say why.
(i) Tourist guide, dhobi, tailor, potter
(ii) Teacher, doctor, vegetable vendor, lawyer
(iii) Postman, cobbler, soldier, police constable
(iv) MTNL, Indian Railways, Air India, SAHARA Airlines, All India Radio
(i) Tourist guide, dhobi, tailor, potter
Ans:- Tourist guide
(ii) Teacher, doctor, vegetable vendor, lawyer
Ans:- vegetable vendor
(iii) Postman, cobbler, soldier, police constable
Ans:- cobbler
(iv) MTNL, Indian Railways, Air India, SAHARA Airlines, All India Radio
Ans:- Indian Railways
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 5
5. A research scholar looked at the working people in the city of Surat and found
the following.
Place of work
In offices and factories registered
with the government
Own shops, office, clinics marketplaces with formal license
People working on the street,
construction workers, domestic
workers
Working in small workshops
usually not registered with the
government
Nature of employment
Organised, Unorganized,Unorganised
Percentage of working people
15
15
20
Nature of employment
Complete the table. What is the percentage of workers in the unorganised
sector in this city?
Ans:-Nearly 80 percent.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 6
6. Do you think the classification of economic activities into primary, secondary and tertiary is useful? Explain how.
Ans:-The classification of economic activities primary, secondary, and tertiary tells about the basic difference as when we produce a good by exploiting natural resources, it is an activity of the primary sector. For example, the cultivation of cotton. It takes place within a crop season. For the growth of the cotton plant, we depend mainly, but not entirely, on natural factors like rainfall, sunshine and climate. The product of this activity, cotton, is a natural product. Similarly, in the case of an activity like dairy, we are dependent on the biological process of the animals and availability of fodder etc. The product here, milk, also is a natural product. Similarly, minerals and ores are also natural products. When we produce a good by exploiting natural resources, it is an activity of the primary sector. the next step after primary is known as Secondary Sector. The secondary sector covers activities in which natural products are changed into other forms through ways of manufacturing that we associate with industrial activity. For example, using cotton fibre from the plant, spin yarn and weave cloth. Using sugarcane as a raw material, we make sugar or gur. We convert earth into bricks and use bricks to make houses and buildings. Since this sector gradually became associated with the different kinds of industries that came up, it is also called as industrial sector. After primary and secondary, there is a third category of activities that falls under tertiary sector and is different from the above two. These are activities that help in the development of the primary and secondary sectors. These activities, by themselves, do not produce a good but they are an aid or a support for the production process. For example, goods that are produced in the primary or secondary
sector would need to be transported by trucks or trains and then sold in wholesale and retail shops. Hence by seeing the basic difference between these three category we can say that all are useful in case of development our self or for country development.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 7
7. For each of the sectors that we came across in this chapter why should one focus on employment and GDP? Could there be other issues which should be examined? Discuss.
Ans:-The employment and GDP of any country tells about the original condition of that country. The value of final goods and services produced in each sector during a particular year provides the total production of the sector for that year. And the sum of production in the three sectors gives
what is called the Gross Domestic Product (GDP) of a country. GDP shows how big the economy is. In India, the mammoth task of measuring GDP is undertaken by a central government ministry. This Ministry, with the help of various government departments of all the Indian states and union territories, collects information relating to total volume of goods and services and their prices and then estimates the GDP. most of the goods produced were natural products from the primary sector and most people were also employed in this sector. So that we can say that GDP is also related with each other i.e, GDP and employment is mutually dependent. As production in all the three sectors has increased, it has increased the most in the tertiary sector. as income levels rise, certain sections of people start demanding many more services like eating out, tourism, shopping, private hospitals, private schools, professional training etc. certain new services such as those based on information and
Communication technology has become important and essential. The production of these services has been rising rapidly. Industrial output or the production of goods went up by eight times during the period; employment in the industry went up by only 2.5 times. Apart from these GDP and employment I think another classification is to consider whether people are working in organised or unorganised sectors.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 8
8. Make a long list of all kinds of work that you find adults around you doing for a living. In what way can you classify them? Explain your choice.
Ans:- The classification is to consider whether adults people are working in organised or unorganised sectors.
The adult peoples are working around us are as,
1.ShopOwners
2.Casual Workers
3. Vegetable Vendors,
4. Workshop mechanics,
5.Domestic workers
6.Tailor
7.Basket weaver
8. Flower cultivator
9.Milk vendor
10. Fishermen
11.Priest
12. Workers in match factory
13. Money lender
14. Gardener
15.Potter
16. Bee-keeper
17. Astronaut
18.Call centre employee
19. Courier
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 9
9. How is the tertiary sector different from other sectors? Illustrate with a few examples.
Ans:-There are three sector in which tertiary sector is one of the most important for development of any country. Because we know that for every country GDP depends upon the workers. Here After primary and secondary, there is a third category of activities that falls under tertiary sector and is different from the above two. These are activities that help in the development of the primary and secondary sectors. These activities, by themselves, do not produce a good but they are an aid
or a support for the production process. For example, goods that are produced in the primary or secondary sector would need to be transported by trucks or trains and then sold in wholesale and retail shops. At times, it may be necessary to store these in godowns. We also may need to talk to others over telephone or send letters (communication) or borrow money from banks (banking) to help production and trade. Transport, storage, communication, banking, trade are some examples of tertiary activities. Since these activities generate services rather than goods, the tertiary sector is also called the service sector. And hence we can classify the tertiary sector from other two primary and secondary sector.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 10
10. What do you understand by disguised unemployment? Explain with an example each from the urban and rural areas.
Ans:-When underemployment is hidden in contrast to someone who does not have a job and is clearly visible as unemployed. Hence, it is also called disguised unemployment.
In case of urban areas there are thousands of casual workers in the service sector in urban areas who search for daily employment. They are employed as painters, plumbers, repair persons and others doing odd jobs. Many of them don’t find work everyday. They may spend the whole day but earn very little. In case of rural areas if we are to improve the health situation, we need many more doctors, nurses, health workers etc. to work in rural areas. These are some ways by which jobs would be created and we would also be able to address the important aspects of development the central government in India recently made a law implementing the Right to Work in 200 districts of India. It is called National Rural Employment Guarantee Act 2005 (NREGA 2005). Under REGA 2005, all those who are able to, and are in need of, work have been guaranteed 100 days of employment in a year by the government. If the government fails in its duty to provide employment, it will give unemployment allowances to the people. The types of work that would in future help to increase the production from land will be given preference under the Act.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 11
11. Distinguish between open unemployment and disguised unemployment.
Ans:- The central government in India recently made a law implementing the Right to Work in 200 districts of India. It is called National Rural Employment Guarantee Act 2005 (NREGA 2005). Under NREGA 2005, all those who are able to, and are in need of, work have been guaranteed 100 days of employment in a year by the government. If the government fails in its duty to
provide employment, it will give unemployment allowances to the people and it is called as Open Unemployment. When underemployment is hidden in contrast to someone who does not
have a job and is clearly visible as unemployed. Hence, it is also called disguised unemployment.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 36 - Q 12
12. “Tertiary sector is not playing any significant role in the development of Indian economy.” Do you agree? Give reasons in support of your answer.
Ans:- Under tertiary sector and is different from the above two. These are activities that help in the development of the primary and secondary sectors. These activities, by themselves, do not produce a good but they are an aid or a support for the production process. For example, goods that are produced in the primary or secondary sector would need to be transported by trucks or trains and then sold in wholesale and retail shops. At times, it may be necessary to store these in
godowns. Transport, storage, communication, banking, trade are some examples of tertiary
activities. The tertiary sector is also called the service sector. Service sector also includes some essential services that may not directly help in the production of goods. The service sector has become the most important in terms of total production. Most of the working people are also employed in the service sector. This is the general pattern observed in developed countries. Hence by the help of these reasons we can say that Tertiary sector is not playing any significant role in the development of Indian economy.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 13
13. Service sector in India employs two different kinds of people. Who are these?
Ans:- At one end there are a limited number of services that employ highly skilled and educated workers It is termed as in organized sector . While At the other end, there are a very large number of workers engaged in services such as small shopkeepers, repair persons, transport persons, etc. It is termed as I unorganized sector.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 14
14. Workers are exploited in the unorganised sector. Do you agree with this view? Give reasons in support of your answer.
Ans:- The unorganized sector is characterised by small and scattered units which are largely
outside the control of the government. There are rules and regulations but these are not followed. Jobs here are low-paid and often not regular. There is no provision for overtime, paid leave, holidays, leave due to sickness etc. Employment is not secure. People can be asked to leave without any reason. When there is less work, such as during some seasons, some people may be asked to leave. Hence we can say that Workers are exploited in the unorganised sector.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 15
15. How are the activities in the economy classified on the basis of employment conditions?
Ans:-On the basis of employment condition the activities in the economy is classified in two groups1.Organised sector 2. unorganised sector. Organised sector covers those enterprises or places of work where the terms of employment are regular and therefore, people have assured work. They are registered by the government and have to follow its rules and regulations which are given in various laws such as the Factories Act, Minimum Wages Act, Payment of Gratuity Act, Shops and Establishments Act etc. It is called organised because it has some formal processes and procedures. Some of these people may not be employed by anyone but may work on their own but they too have to register themselves with the government and follow the rules and regulations. But in case of Unorganised sector The unorganized sector is characterised by small and scattered units which are largely outside the control of the government. There are rules and regulations but these are not followed. Jobs here are low-paid and often not regular. There is no provision for overtime, paid leave, holidays, leave due to sickness etc. Employment is not secure. People can be asked to leave without any reason.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 16
16. Compare the employment conditions prevailing in the organised and unorganized sectors.
Ans:- Organised sector covers those enterprises or places of work where the terms of employment are regular and therefore, people have assured work. They are registered by the government and have to follow its rules and regulations which are given in various laws such as the Factories Act, Minimum Wages Act, Payment of Gratuity Act, Shops and Establishments Act etc. It is called organised because it has some formal processes and procedures. Some of these people may not be employed by anyone but may work on their own but they too have to register themselves with the government and follow the rules and regulations. Workers in the organised sector enjoy security of employment. They are expected to work only a fixed number of hours. If they work more, they have to be paid overtime by the employer. They also get several other benefits from the employers. in the unorganised sector. But in case of unorganized sector, It is characterised by small and scattered units which are largely outside the control of the government. There are rules and regulations but these are not followed. Jobs here are low-paid and often not regular. There is no provision for overtime, paid leave, holidays, leave due to sickness etc. Employment is not secure. People can be asked to leave without any reason.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 17
17. Explain the objective of implementing the NREGA 2005.
Ans:- The central government in India made a law implementing the Right to Work in 200 districts of India. It is called National Rural Employment Guarantee Act 2005 (NREGA 2005). Under NREGA 2005, all those who are able to, and are in need of, work have been guaranteed 100 days of employment in a year by the government. If the government fails in its duty to provide employment, it will give unemployment allowances to the people. The types of work that would in future help to increase the production from land will be given preference under the Act.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 18
18. Using examples from your area compare and contrast that activities and functions of private and public sectors.
Ans:-Private Sectors Activities in the private sector are guided by the motive to earn profits. To get such services we have to pay money to these individuals and companies. private sector will not provide at a reasonable cost. The private sector may not continue their production or business unless
government encourages it. For example, selling electricity at the cost of generation may push up the costs of production of industries. Many units, especially small-scale units, might have to shut down. Government here steps in by producing and supplying electricity at rates which these industries can afford. Government has to bear part of the cost. In the public sector, the government owns most of the assets and provides all the services. Railways or post office is an example of the public
sector. Tata Iron and Steel Company Limited (TISCO) or Reliance Industries Limited (RIL) are privately owned. Tata Iron and Steel Company Limited (TISCO) or Reliance Industries
Limited (RIL) are privately owned.Construction of roads, bridges, railways, harbours, generating electricity, providing irrigation through dams etc. Thus, governments have to undertake such heavy spending and ensure that these facilities are available for everyone.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 19
19. Discuss and fill the following table giving one example each from your area.
Well managed organisation Badly managed organisation
Public sector
Private Sector
Ans:- Well managed organization- Public sector example, post office where In the public sector, the government owns most of the assets and provides all the services. The purpose of the public sector is not just to earn profits. Governments raise money through taxes and other ways to meet expenses on the services rendered by it. Modern day governments spend on a whole range of activities. Government here steps in by producing and supplying electricity at rates which these industries can afford. Government has to bear part of the cost. The government must spend on these.
Providing health and education facilities for all is one example. the duty of the government to take care of the poorest and most ignored regions of the country through increased spending in such areas. While in case of Badly managed organization- Private Sector, Tata Iron and Steel Company Limited (TISCO) or Reliance Industries Limited (RIL) are privately owned. Tata Iron and Steel Company Limited (TISCO) or Reliance Industries Limited (RIL) are privately owned. construction of
roads, bridges, railways, harbours, generating electricity, providing irrigation through dams etc. Thus, governments have to undertake such heavy spending and ensure that these facilities are available for
everyone.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 20
20. Give a few examples of public sector activities and explain why the government has taken them up.
Ans:- Railways or post office is an example of the public sector. The purpose of the public sector is not just to earn profits. Governments raise money through taxes and other ways to meet expenses on the services rendered by it. Modern day governments spend on a whole range of activities. There are several things needed by the society as a whole but which the private sector will not provide at a reasonable cost. construction of roads, bridges, railways, harbours, generating electricity, providing irrigation through dams etc. Thus, governments have to undertake such heavy spending and ensure that these facilities are available for everyone. There are some activities, which the government has to support. So that government has taken them up.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 21
21. Explain how public sector contributes to the economic development of a nation.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 22
22. The workers in the unorganised sector need protection on the following issues : wages, safety and health. Explain with examples.
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 23
23. A study in Ahmedabad found that out of 15,00,000 workers in the city, 11,00,000 worked in the unorganised sector. The total income of the city in this year (1997-1998) was Rs 60,000 million. Out of this Rs 32,000 million was generated in the organised sector. Present this data as a table. What kind of ways should be thought of for generating more employment in the city?
CBSE 10th Economics - Chap 2 - Sector Of The Indian Economy - Page 37 - Q 24
24. The following table gives the GDP in Rupees (Crores) by the three sectors:
Year primary secondary tertiary
1950 80,000 19,000 39,0002000 3,14,000 2,80,000 5,55,000
(i) Calculate the share of the three sectors in GDP for 1950 and 2000.
(ii) Show the data as a bar diagram similar to Graph 2 in the chapter.
(iii) What conclusions can we draw from the bar graph?
CBSE 10th Economics - Chap 3 - Money And Credit
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 1
1. In situations with high risks, credit might create further problems for the borrower. Explain.
Ans:- Farmers usually take crop loans at the beginning of the season and repay the loan after harvest. Repayment of the loan is crucially dependent on the income from farming.The failure of the crop made loan repayment impossible. The sell part of the land to repay the loan. Credit, instead of helping improve her earnings, left her worse off. Credit in this case pushes the borrower into a situation from which recovery is very painf. In one situation, because of the crop failure, credit pushes the person into a debt trap. To repay loan to sell a portion of land. It is clearly much worse off than before. Whether credit would
be useful or not, therefore, depends on the risks in the situation and whether there is some support,
in case of loss. repayment of the principal. In addition, lenders may demand collateral (security) against loans. Collateral is an asset that the borrower owns (such as land, building, vehicle, livestocks,deposits with banks) and uses this as a guarantee to a lender until the loan is repaid. If the borrower fails to repay the loan, the lender has the right to sell the asset or collateral to obtain payment. Property such as land titles, deposits with banks, livestock are some common examples of collateral used for borrowing.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 2
2. How does money solve the problem of double coincidence of wants? Explain with an example of your own.
Ans:- Money acts as an intermediate in the exchange process, it is called a medium of exchange. Money solve the problem of double coincidence of wants which can be understand by this way as for example, It is not necessary for the cloth manufacturer to look for a farmer who will buy his cloth and at the same time sell him Rice. All he has to do is find a buyer for his cloth. Once he has exchanged his shoes for money, he can purchase Rice or any other commodity in the market. Hence money will eliminate the problem which can be produce by double coincidence of wants and manufacturer can buy anything which they wants .Manufacturer will not depend on buyers.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 3
3. How do banks mediate between those who have surplus money and those who need money?
Ans:-In the banking system On one side are the depositors who keep their money in the banks and on the other side are the borrowers who take loans from these banks. Banks use the major portion of the deposits to extend loans. There is a huge demand for loans for various economic activities. Banks make use of the deposits to meet the loan requirements of the people. In this way, banks mediate between those who have surplus funds (the depositors) and those who are in need of these funds (the borrowers).
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 4
4. Look at a 10 rupee note. What is written on top? Can you explain this statement?
Ans:-On top of 10 rupee note Reserve Bank Of India is written. Only Reserve Bank of India has the authority to publish currency notes as per Indian Government laws.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 5
5. Why do we need to expand formal sources of credit in India?
Ans:- For expansion of formal sources of credit in India it is necessary that banks and cooperatives increase their lending particularly in the rural areas, so that the dependence on informal sources of credit reduces. Secondly, while formal sector loans need to expand, it is also necessary that everyone receives these loans. At present, it is the richer households who receive formal credit whereas the poor have to depend on the informal sources. It is important that the formal credit is distributed more equally so that the poor can benefit from the cheaper loans.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 6
6. What is the basic idea behind the SHGs for the poor? Explain in your own words.
Ans:-Here basic idea behind the SHGs can be understand by this way, as SHG means SELP-HELP GROUP that means In recent years, people have tried out some newer ways of providing loans to the poor. A typical SHG has 15-20 members, usually belonging to one neighbourhood, who meet and save regularly. Saving per member varies from Rs 25 to Rs 100 or more, depending on the ability of the people to save. Members can take small loans from the group itself to meet their needs. After some time these group creates self employment opportunities for the members. Small loans are provided to the members for
releasing mortgaged land, for meeting working capital needs (e.g. buying seeds, fertilisers, raw materials like bamboo and cloth), for housing materials, Also, it is the group which is responsible for the repayment of the loan. Thus, the SHGs help borrowers overcome the problem of lack of collateral.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 7
7. What are the reasons why the banks might not be willing to lend to certain borrowers?
Ans:- Banks are not present everywhere in rural India. Even when they are present, getting a
loan from a bank is much more difficult than taking a loan from informal sources. Bank loans require proper documents and collateral. Absence of collateral is one of the major reasons which prevents the poor from getting bank loans. Thus, if any person have not proper document and collateral then bank might not be willing to lend to certain borrower.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 8
8. In what ways does the Reserve Bank of India supervise the functioning of banks? Why is this necessary?
Ans:- The Reserve Bank of India supervises the functioning of formal sources of loans. For instance, Banks maintain a minimum cash balance out of the deposits they receive. The RBI monitors that the banks actually maintain the cash balance. Similarly, the RBI sees that the banks give loans not just to profit-making businesses and traders but also to small cultivators, small scale industries, tosmall borrowers etc. Periodically, banks have to submit information to the RBI on how much they are lending, to whom, at what interest rate, etc. It is necessary because, There is no organisation which supervises the credit activities of lenders in the informal sector. They can lend at whatever interest rate they choose. There is no one to stop them from using unfair means to get their money back. So that Reserve Bank Of India supervise the functioning of bank.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 9
9. Analyse the role of credit for development.
Ans:-The role of credit for development can be understand by this way, Credit is a crucial element in economic life and it is therefore important for every person. The other crucial issue of credit is its availability to all, especially the poor, and on reasonable terms. Credit (loan) refers to an agreement in which the lender supplies the borrower with money, goods or services in return for the promise of future payment. The credit helps him to meet the ongoing expenses of production, complete production on time, and thereby increase his earnings. Credit therefore plays a vital and positive role in this situation. A large number of transactions in our day-to-day activities involve credit in some form or the other the main demand for credit is for crop production. credit pushes the borrower into a situation from which recovery is very painful. In one situation credit helps to increase earnings and therefore the person is better off than before. In another situation, because of the crop failure, credit pushes the person into a debt trap. Cheap and affordable credit
is crucial for the country’s development. It is important that the formal credit is distributed
more equally so that the poor can benefit from the cheaper loans. Thus, we can say that development of any country depends upon the credit.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 10
10. Manav needs a loan to set up a small business. On what basis will Manav decide whether to borrow from the bank or the moneylender? Discuss.
Ans:-As for my point of view I think it would be better for Manav to borrow the money from bank Instead of moneylender because, banks and cooperative societies need to lend more. This would lead to higher incomes and many people could then borrow cheaply for a variety of needs. They could grow crops, do business, set up small-scale industries etc. They could set up new industries or trade in goods. Hence due to these all above reasons we can say that bank will be better option in case of money lending for setting any small business.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 11
11. In India, about 80 per cent of farmers are small farmers, who need credit for cultivation.
(a) Why might banks be unwilling to lend to small farmers?
(b) What are the other sources from which the small farmers can borrow?
(c) Explain with an example how the terms of credit can be unfavourable for the small farmer.
(d) Suggest some ways by which small farmers can get cheap credit.
(a) Why might banks be unwilling to lend to small farmers?
Ans:-Bank will be unwillingly to lend to small farmer as poor person because, bank loans require proper documents and collateral. And in absence of collateral is one of the major reasons which prevents the poor from getting bank loans.
(b) What are the other sources from which the small farmers can borrow?
Ans:-The other sources from which the small farmer borrow the money is comes under informal sources, other than bank and cooperative societies like moneylenders, traders, employers, relatives and friends, etc.
(c) Explain with an example how the terms of credit can be unfavourable for the small farmer.
Ans:- Every loan agreement specifies an interest rate which the borrower must pay to the lender along with the repayment of the principal. In addition, lenders may demand collateral (security) against loans. Collateral is an asset that the borrower owns (such as land, building, vehicle, livestocks, deposits with banks) and uses this as a guarantee to a lender until the loan is repaid. If the borrower fails to repay the loan, the lender has
the right to sell the asset or collateral to obtain payment. Property such as land titles, deposits with banks,
livestock are some common examples of collateral used for borrowing. But as we know that poor farmer does not have such asset so that the terms of credit becomes unfavourable for the small farmer. As for example Housing Loan if any small farmer wants to make his home then they have to fulfill some terms and condition as The annual interest rate on the loan is 12 per cent and the loan is to be repaid in 10 years in monthly instalments. They have to submit to the bank, documents and employment records and salary
before the bank agreed to give him the loan. But due to absence of these document and salary report a small farmer can not get Housing loan.
(d) Suggest some ways by which small farmers can get cheap credit.
Ans:- The other major source of cheap credit in rural areas are the cooperative societies (or cooperatives). Members of a cooperative pool their resources for cooperation in certain areas. There are several types of cooperatives possible such as farmers cooperatives, weavers cooperatives, industrial workers cooperatives, etc.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 12
12. Fill in the blanks:
(i) Majority of the credit needs of the ____households are met from informal sources.
(ii) ____costs of borrowing increase the debt-burden.
(iii) _____ issues currency notes on behalf of the CentralGovernment.
(iv) Banks charge a higher interest rate on loans than what they offer on ______.
(v) _______ is an asset that the borrower owns and uses as a guarantee until the loan is repaid to the lender.
(i) Majority of the credit needs of the __poor_households are met from informal sources.
(ii) ____Higher_____costs of borrowing increase the debt-burden.
(iii) _Reserve Bank Of India_issues currency notes on behalf of the Central Government.
(iv) Banks charge a higher interest rate on loans than what they offer on _deposits_.
(v) _Collateral___ is an asset that the borrower owns and uses as a guarantee until the loan is repaid to the lender.
CBSE 10th Economics - Chap 3 - Money And Credit - Page 52 - Q 13
13.Choose the most appropriate answer.
(i) In a SHG most of the decisions regarding savings and loan activities are taken by
(a) Bank.
(b) Members.
(c) Non-government organisation.
(ii) Formal sources of credit does not include
(a) Banks.
(b) Cooperatives.
(c) Employers.
Ans: (i) - b
(ii) - c
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 1
1 What do you understand by globalisation? Explain in your own words.
Ans:- Globalisation defines as the integration between countries through foreign trade and foreign investments by multinational corporations (MNCs). MNCs have been a major force in the globalisation process connecting distant regions of the world. MNCs are playing a major role in the globalisation process. More and more goods and services, investments and technology are moving between countries. Besides the movements of goods, services, investments and technology, there is one more way in which the countries can be connected. This is through the movement of people between countries. People usually move from one country to another in search of better income, better jobs or better education. Rapid improvement in technology has been one major factor that has stimulated the globalisation process. While globalisation has benefited well-off consumers and also producers with skill, education and wealth, many
small producers and workers have suffered as a result of the rising competition. Fair globalisation would create opportunities for all, and also ensure that the benefits of globalisation are shared better. globalisation has created opportunities for paid work for women,. For a large number of small producers and workers globalisation has posed major challenges. Moreover, globalisation has enabled some large Indian companies to emerge as multinationals themselves! Tata Motors (automobiles), Infosys (IT), Ranbaxy (medicines), Asian Paints (paints), Sundaram Fasteners (nuts and bolts) are some Indian companies which are spreading their operations worldwide.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 2
2. What were the reasons for putting barriers to foreign trade and foreign investment by the Indian government? Why did it wish to remove these barriers?
Ans:-The reason for putting barriers to foreign trade and foreign investment by the Indian government for protecting the producers. Tax on imports is an example of trade barrier. Governments can use trade
barriers to increase or decrease (regulate) foreign trade .The barriers on foreign trade and foreign investment were removed to a large extent. This meant that goods could be imported and exported easily and also foreign companies could set up factories and offices here. Barriers to foreign trade and foreign investment was considered necessary to protect the producers within the country from foreign competition. Removing barriers or restrictions set by the government is what is known as liberalisation. With liberalisation of trade, businesses are allowed to make decisions freely about what they wish to import or
export.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 3
3. How would flexibility in labour laws help companies?
Ans:- Government has also allowed flexibility in the labour laws to attract foreign investment. In the recent years, the government has allowed companies to ignore many of these. Instead of hiring workers on a regular basis, companies hire workers ‘flexibly’ for short periods when there is intense pressure of work. This is done to reduce the cost of labour for the company. As the labour cost reduces then automatically company will goes on progress.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 4
4. What are the various ways in which MNCs set up, or control, production in other countries?
Ans:- MNCs set up production jointly with some of the local companies of these countries. There’s another way in which MNCs control production. Large MNCs in developed countries place orders for production with small producers. Garments, footwear, sports items are examples of industries where production is carried out by a large number of small producers around the world. Variety of ways in which the MNCs are spreading their production and interacting with local producers in various countries across the globe.are –
1. By setting up partnerships with local companies,2. By using the local companies for supplies,3. By closely competing with the local companies or buying them up, MNCs are exerting a strong influence on production
at these distant locations.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 5
5. Why do developed countries want developing countries to liberalise their trade and investment? What do you think should the developing countries demand in return?
Ans:- Globalisation is the process of rapid integration of countries. This is happening through greater foreign trade and foreign investment. Technology, particularly IT, has played a big role in organising production across countries. In addition, liberalisation of trade and WTO has put pressure on developing countries to liberalise trade and investment. Removing barriers or restrictions set by the government is what is known as liberalisation. With liberalisation of trade, businesses are allowed to make decisions freely about what they wish to import or export .As The government imposes much less restrictions than before and is therefore said to be more liberal. Developing countries have already various method of improvement his country. So I think there should no reason of demand in terms of demand.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 6
6. “The impact of globalisation has not been uniform.” Explain this statement.
Ans:- The impact of globalisation has not been uniform. Globalisation and greater competition among producers – both local and foreign producers .Firstly, MNCs have increased their investments in India over the past 15 years, which means investing in India has been beneficial for them. MNCs have been interested in industries such as cell phones, automobiles, electronics, soft drinks, fast food or services such as banking in urban areas. These products have a large number of well-off buyers. In these industries and services, new jobs have been created. Due to these all reason we can say that The impact of globalisation is not uniform.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 7
7. How has liberalisation of trade and investment policies helped the globalization process?
Ans:-The liberalization of trade and investment policies helped the globalization process we can understand it by this way The Indian government, after Independence, had put barriers to foreign trade and foreign investment. This was considered necessary to protect the producers within the country from foreign competition. Competition from imports at that stage would not have allowed these industries to come up. Thus, India allowed imports of only essential items such as machinery, fertilisers, petroleum etc. The government decided that the time had come for Indian producers to compete with producers around the globe. It felt that competition would improve the performance of producers within the country since they would have to improve their quality. This decision was supported by powerful international organisations. Thus, barriers on foreign trade and foreign investment were removed to a large extent. This meant that goods could be imported and exported easily and also foreign companies could set up factories and offices here. Removing barriers or restrictions set by the government is what is known as liberalisation. With liberalisation of trade, businesses are allowed to make decisions freely about what they wish to import or export.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 8
8. How does foreign trade lead to integration of markets across countries? Explain with an example other than those given here.
Ans:- Most regions of the world are getting increasingly interconnected. While this interconnectedness across countries has many dimensions cultural, political, social and economic, globalisation in a more limited
sense. It defines globalisation as the integration between countries through foreign trade and foreign investments by multinational corporations (MNCs).Here foreign trade showing the important role in case of integration, foreign trade creates an opportunity for the producers to reach beyond the domestic markets, i.e., markets of their own countries. Producers can sell their produce not only in markets located within the country but can also compete in markets located in other countries of the world. Similarly, for the buyers, import of goods produced in another country is one way of expanding the choice of goods beyond what is domestically produced. Foreign trade lead to integration of markets across countries can be explained by this way As Japan exports plastic toys in India. Buyers in India now have the option of choosing between the Indian toys and the Japanies toys. Because of the cheaper prices and new designs, Japanese toys become more popular in the Indian markets. Toys are now cheaper in the Indian markets than earlier. As a result of trade, Japanies toys come into the Indian markets. In the competition between Indian and Japanies toys, Japanies toys prove better.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 9
9. Globalisation will continue in the future. Can you imagine what the world would be like twenty years from now? Give reasons for your answer.
Ans:- Globalisation is this process of rapid integration or interconnection between countries .And MNCs are playing a major role in the globalisation process. More and more goods and services, investments and technology are moving between countries. Most regions of the world are in closer contact with each other than a few decades back. Fair globalisation would create opportunities for all, and also ensure that the benefits of globalisation are shared better. As I think after twenty year from now the world would be in better position in case of production of goods and services because For instance, the government can ensure that labour laws are properly implemented and the workers get their rights. It can support small producers to improve their performance till the time they become strong enough to compete. The government can use trade and investment barriers. It can negotiate at the WTO for ‘fairer rules’. Hence the country would become a developed one.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 10
10. Supposing you find two people arguing: One is saying globalisation has hurt our country’s development. The other is telling, globalisation is helping India develop. How would you respond to these organisations?
Ans:-In this case I will give my opinion, as here various examples can prove that globalisation makes country strong there is an example of Chinese toy in India. As a result of trade, Chinese toys come into the Indian markets. In the competition between Indian and Chinese toys, Chinese toys prove better. Chinese toys prove better. Indian buyers have a greater choice of toys and at lower prices. For the Chinese toy makers, this provides an opportunity to expand business. There is greater choice before these consumers who now enjoy improved quality and lower prices for several products. As a result, these people today, enjoy much higher standards of living than was possible earlier. Hence I can say that the people of country enjoying due to globalization .Also it helps in development of country.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 11
11. Fill in the blanks.
Indian buyers have a greater choice of goods than they did two decades back. This
is closely associated with the process of ___________. Markets in India are selling
goods produced in many other countries. This means there is increasing _________ with other countries. Moreover, the rising number of brands that we see in the markets might be produced by MNCs in India. MNCs are investing in India because these produdts have large no of well-off buyers .____________have more choices in the market, the effect of rising _______________and ______________has meant greater _________________among the producers.
Indian buyers have a greater choice of goods than they did two decades back. This is closely associated with the process of Foreign Trade . Markets in India are selling goods produced in many other countries. This means there is increasing Interconnection with other countries. Moreover, the rising number of brands that we see in the markets might be produced by MNCs in India. MNCs are investing in India because these products have large no of well-off buyers. While consumers have more choices in the market, the effect of rising foreign trade and foreign investment has meant greater competition among the producers.
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 12
12.Match the following.
(i) MNCs buy at cheap rates from small (a) Automobiles
producers
(ii) Quotas and taxes on imports are used to (b) Garments, footwear, sports
regulate trade items
(iii) Indian companies who have invested abroad (c) Call centres
(iv) IT has helped in spreading of (d) Tata Motors, Infosys, Ranbaxy
production of services
(v) Several MNCs have invested in setting (e) Trade barriers up factories in India for production
Ans- (i)-(b),(ii)-(e),(iii)-(d),(iv)-(c),(v)-(a)
CBSE 10th Economics - Chap 4 - Globalisation And The Indian Economy - Page 72 - Q 13
13.Choose the most appropriate option.
(i) The past two decades of globalisation has seen rapid movements in
(a) goods, services and people between countries.
(b) goods, services and investments between countries.
(c) goods, investments and people between countries.
(ii) The most common route for investments by MNCs in countries around the world is to
(a) set up new factories.
(b) buy existing local companies.
(c) Form partnerships with local companies.
(iii) Globalisation has led to improvement in living conditions
(a) of all the people
(b) of people in the developed countries
(c) of workers in the developing countries
(d) none of the above
Ans:-(i)-(b),(ii)-(c),(iii)-(d)
CBSE 10th Economics - Chap 5 - Consumer Right
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 1
1. Why are rules and regulations required in the marketplace? Illustrate with a few examples.
Ans:-Rules and Regulations required in the marketplace for protection of workers in the unorganised sector or to protect people from high interest rates charged by moneylenders in the informal sector. Similarly, rules and regulations are also required for protecting the environment. For example, moneylenders in the informal sector that you adopt various tricks to bind the borrower: they could make the producer sell the produce to them at a low rate in return for a timely loan; they could force a small farmer to sell her land to pay back the loan. for other example many people who work in the unorganised sector have to work at a low wage and accept conditions that are not fair and are also often harmful to their health. To prevent such exploitation, we have talked of rules and regulations for their protection. Likewise, rules and regulations are required for the protection of the consumers in the marketplace. For example,a long battle had to be fought with court cases to make cigarette manufacturing companies accept that their product could cause cancer.Hence, there is a need for rules and regulations to ensure protection for consumers.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 2
2. What factors gave birth to the consumer movement in India? Trace its evolution.
Ans:- In India, the consumer movement as a ‘social force’ originated with the necessity of protecting and promoting the interests of consumers against unethical and unfair trade practices. Rampant food shortages, hoarding, black marketing, adulteration of food and edible oil gave birth to the consumer movement in an organised form in the 1960.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 3
3. Explain the need for consumer consciousness by giving two examples.
Ans:-The need for consumer consciousness can be explain by this way, to protect people from high interest rates charged by moneylenders in the informal sector. as many unfair practices were being indulged in by the sellers. There was no legal system available to consumers to protect them from exploitation in the marketplace. For example, if we buy a product and find it defective well within the expiry period, we can ask for a replacement. If the expiry period was not printed, the manufacturer would blame the shopkeeper and will not accept the responsibility. another example If people sell medicines that have expired severe action can be taken against them. Similarly, one can protest and complain if someone sells a good at more than the printed price on the packet. This is indicated by ‘MRP’ — maximum retail price. In fact consumers can bargain with the seller to sell at less than the MRP.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 4
4. Mention a few factors which cause exploitation of consumers.
Ans:- Exploitation of consumers in the marketplace happens in various ways. For example, sometimes traders indulge in unfair trade practices such as when shopkeepers weigh less than what they should or when traders add charges that were not mentioned before, or when adulterated/defective goods are sold. Thus these above are the factors which causes exploitation of consumers.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 5
5. What is the rationale behind the enactment of Consumer Protection Act 1986?
Ans:- In India, the consumer movement as a ‘social force’ originated with the necessity of protecting and promoting the interests of consumers against unethical and unfair trade practices. consumer organisations were largely engaged in writing articles and holding exhibitions. They formed consumer groups to look into the malpractices in ration shops and overcrowding in the road passenger transport. More recently, India witnessed an upsurge in the number of consumer groups. Because of all these efforts, the movement succeeded in bringing pressure on business firms as well as government to correct business conduct which may be unfair and against the interests of consumers at large. A major step taken in 1986 by the Indian government was the enactment of the Consumer Protection Act 1986, popularly known as COPRA. Thus we can see that the above represented conditions arises the enactment of Consumer Protection Act 1986.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 6
6. Describe some of your duties as consumers if you visit a shopping complex in your locality.
Ans:- we as consumers, and if we visit a shopping complex, then I have the right to be protected against the marketing of goods and delivery of services that are hazardous to life and property. There are many goods and services that we purchase that require special attention to safety suppose if we want to buy pressure cooker then we see the safety valve which, if it is defective, can cause a serious accident. The manufacturers of the safety valve have to ensure high quality. We also need public or government action to see that this quality is maintained. if we buy a product and find it defective well within the expiry period, we will ask for a replacement. If the expiry period was not printed, if we sells a good at more than the printed price on the packet. This is indicated by ‘MRP’ — maximum retail price. In fact we will bargain with the seller to sell at less than the MRP.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 7
7. Suppose you buy a bottle of honey and a biscuit packet. Which logo or mark you will have to look for and why?
Ans:- If we buy a bottle of honey and a biscuit packet that time we see logo or mark as ISI, Agmark or Hallmark on that because, These logos and certification help consumers get assured of quality while purchasing the goods and services. The organisations that monitor and issue these certificates allow producers to use their logos provided they follow certain quality standards. Though these organisations develop quality standards for many products, As for example LPG, Food Product, Drinking Water etc.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 8
8. What legal measures were taken by the government to empower the consumers in India?
Ans:- When we as consumers become conscious of our rights, while purchasing various goods and services. The enactment of COPRA has led to the setting up of separate departments of Consumer Affairs in central and state governments. Under COPRA, a three-tier quasi judicial machinery at the district,state and national levels was set up for redressal of consumer disputes. The district level court deals with the cases involving claims upto Rs 20 lakhs, the state level courts between Rs 20 lakhs and Rs 1 crore and the national level court deals with cases involving claims exceeding Rs 1 crore. If a case is dismissed in district level court, the consumer can also appeal in state and then in National level courts. Thus, the Act has enabled us as consumers to have the right to represent in the consumer courts.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 9
9. Mention some of the rights of consumers and write a few sentences on each.
Ans:- Consumers have rights that they can complain and ask for compensation or replacement if the product proves to be defective in any manner. we as consumers, have the right to be protected against the marketing of goods and delivery of services that are hazardous to life and property. Due to negligence by the doctors and staff in giving anaesthesia, crippled a student for life. If we are using many goods and services, we purchase that require special attention to safety. For example, pressure cookers have a safety valve which, if it is defective, can cause a serious accident. The manufacturers of the safety valve have to ensure high quality. You also need public or government action to see that this quality is maintained.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 10
10. By what means can the consumers express their solidarity?
Ans:- Consumer express their solidarity by using their rights which has given by government like, Consumers have rights that they can complain and ask for compensation or replacement if the product proves to be defective in any manner. Consumers have the right to be informed about the particulars of goods and services that they purchase. If people sell medicines that have expired severe action can be taken against them. Similarly,if someone sells a good at more than the printed price on the packet. This is indicated by ‘MRP’ — maximum retail price. In fact consumers can bargain with the seller to sell at less than the MRP. In recent times, the right to information has been expanded to cover various services provided by the Government.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 11
11. Critically examine the progress of consumer movement in India.
Ans:- The consumer movement arose out of dissatisfaction of the consumers as many unfair practices were being indulged in by the sellers. There was no legal system available to consumers to protect them from exploitation in the marketplace. In India, the consumer movement as a ‘social force’ originated with the necessity of protecting and promoting the interests of consumers against unethical and unfair trade practices. More recently, India witnessed an upsurge in the number of consumer groups. Because of all these efforts, the movement succeeded in bringing pressure on business firms as well as government to correct business conduct which may be unfair and against the interests of consumers at large. A major step taken in 1986 by the Indian government was the enactment of the Consumer Protection Act 1986, popularly known as COPRA. It can be examined on the basis of this statement Under COPRA, a three-tier quasi-judicial machinery at the district, state and national levels was set up for redressal of consumer disputes. The district level court deals with the cases involving claims upto Rs 20 lakhs, the state level courts between Rs 20 lakhs and Rs 1 crore and the national level court deals with cases involving claims exceeding Rs 1 crore. If a case is dismissed in district level court, the consumer can also appeal in state and then in National level courts. Thus, the Act has enabled us as consumers to have the right to represent in the consumer courts.
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 12
12. Match the following.
(i) Availing details of ingredients of a product (a) Right to safety
(ii) Agmark (b) Dealing with consumer cases
(iii) Accident due to faulty engine in a scooter (c) Certification of edible oil and cereals
(iv) District Consumer Court (d) Agency that develop standards for goods and services
(v) Consumers International (e) Right to information
(vi) Bureau of Indian Standards (f) Global level institution ofconsumer welfare organizations
Ans(i)-(e),(ii)-(c),(iii)-(a),(iv)-(b),(v)-(f),(vi)-(d)
CBSE 10th Economics - Chap 5 - Consumer Right - Page 87 - Q 13
13. Say True or False.
(i) COPRA applies only to goods.
(ii) India is one of the many countries in the world which has exclusive courts for consumer redressal.
(iii) When a consumer feels that he has been exploited, he must file a case in the District Consumer Court.
(iv) It is worthwhile to move to consumer courts only if the damages incurred are of high value.
(v) Hallmark is the certification maintained for standardisation of jewellry.
(vi) The consumer redressal process is very simple and quick.
(vii) A consumer has the right to get compensation depending on the degree of the damage
i - False
ii - True
iii - True
iv - False
v - True
vi - False
vii - True
CBSE 10TH English
This area should give the introduction of Course
CBSE 10th English - Chap 1 - A Letter to God
NCERT Book Solutions - Thinking of the Text
CBSE English - Chapter 1 - A Letter to God - Page 7 - Q1
1. Who does Lencho have complete faith in? Which sentences in the story tell you this?
Ans. Lencho had complete faith in God.
The sentences in the story which tell us of this are,
1. “But in the hearts of all who lived in that solitary house in the middle of the valley, there was a single hope: help from God.”
2. “All through the night, Lencho thought only of his one hope: the help of God, whose eyes, as he had been instructed, see everything, even what is deep in one’s conscience.”
3.“It was nothing less than a letter to God.”
4. “The following Sunday Lencho came a bit earlier than usual to ask if there was a letter for him.”
5. “Lencho showed not the slightest surprise on seeing the money; such was his confidence — but he became angry when he counted the money. God could not have made a mistake, nor could he have denied Lencho what he had requested.”
CBSE English - Chapter 1 - A Letter to God - Page 7 - Q2
2. Why does the postmaster send money to Lencho? Why does he sign the letter ‘God’?
Ans. The postmaster was quite moved by seeing the faith of Lencho in God. He even wished that he had such faith. So he decided that such faith should not break. That is why when he arranged the money for Lencho and kept it in an envelope, he signed it God, so that Lencho believes that the money he got is sent from God.
CBSE English - Chapter 1 - A Letter to God - Page 7 - Q3
3. Did Lencho try to find out who had sent the money to him? Why/Why not?
Ans. No, Lencho didn’t try to find out who had actually sent the money to him. Such was his faith in god that he was very confident of God helping him. So when he received the money, he was quite sure that it was sent to him by God.
CBSE English - Chapter 1 - A Letter to God - Page 7 - Q4
4. Who does Lencho think has taken the rest of the money? What is the irony in the situation? (Remember that the irony of a situation is an unexpected aspect of it. An ironic situation is strange or amusing because it is the opposite of what is expected.)
Ans. Lencho thought that the rest of money was taken by the post office staffs.
The irony in this is that it were the post office staffs, and specially the post master, who actually had arranged the money for him. And Lencho ignorantly blamed them to have cheated him.
CBSE English - Chapter 1 - A Letter to God - Page 8 - Q5
5. Are there people like Lencho in the real world? What kind of a person would you say he is? You may select appropriate words from the box to answer the question.
greedy naive stupid ungrateful
selfish comical unquestioning
Ans. There should be very few people, if any, in the real world like Lencho.
The best suited word for him in the box is “naïve”. His personality is marked by showing unaffected simplicity and lack of worldly experience.
CBSE English - Chapter 1 - A Letter to God - Page 8 - Q6
6. There are two kinds of conflict in the story: between humans and nature, and between humans themselves. How are these conflicts illustrated?
Ans. The conflict between humans and nature is shown in the story by the incidence when Lencho and his family are so happy with the advent of rain. But then suddenly their happiness disappears as the rain turns into a hail storm and all their crop is destroyed. This shows that humans may wish something to happen, but they are nothing but the puppets in the hand of nature. We can just wish that Nature remains friendly to us and have to accept to whatever comes our way.
The second conflict that is shown between humans themselves is marked by the incidence when Lencho complains to God that the post office staffs cheated him with the money He sent him. Now this shows that though he was so naïve in his approach and had a tremendous faith in God, he didn’t trust his fellow humans.
CBSE 10th English - Chap 2 - Long Walk to Freedom
CBSE English - Chapter 2 - Long Walk to Freedom - Page 24 - Q1
1. Why did such a large number of international leaders attend the inauguration? What did it signify the triumph of?
Ans. It was the occasion of freedom of South Africa from apartheid. It was the first time in the country’s history to have a black president after three centuries of white rule. So, international leaders from over 140 countries had gathered to pay respect.
This signified the triumph of humanity over racism.
CBSE English - Chapter 2 - Long Walk to Freedom - Page 24 - Q2
2. What does Mandela mean when he says he is “simply the sum of all those African patriots” who had gone before him?
Ans. The fight for this freedom was being fought for a long time, even before Mandela came into picture. But the patriots who fought this great battle were no more to see this day. That’s why; Mandela humbly says that this day is the outcome of all those efforts. Since he was there to envision the great day, and be a proud part of it, he says that he is simply the sum (result or outcome) of all those African patriots.
CBSE English - Chapter 2 - Long Walk to Freedom - Page 24 - Q3
3. Would you agree that the “depths of oppression” create “heights of character”? How does Mandela illustrate this? Can you add your own examples to this argument?
Ans. Yes, we agree that the “depth of oppression” creates “heights of character”. Mandela gives the example of great personalities like Oliver Tambos, the Walter Sisulus, the Chief Luthulis, the Yusuf Dadoos, the Bram Fischers, the Robert Sobukwes to put his point and then he illustrates it by giving the example of South Africa as a land of minerals and gems. But he says that all minerals and diamonds are found underneath the soil. By this he means to say that the rocks have to be oppressed by the soil to become minerals and diamonds.
CBSE English - Chapter 2 - Long Walk to Freedom - Page 24 - Q4
4. How did Mandela’s understanding of freedom change with age and experience?
Ans. Mandela talks of three stages in his life. The first one being his childhood, when freedom to him meant running freely in the fields near his mother’s hut; swimming freely in the clear stream that ran through his village; roasting meals freely under the stars and riding the broad backs of slow-moving bulls freely. As long as he obeyed his father and abided by the customs of his tribe, he was not troubled by the laws of man or God.
It was only when he became young enough to think, and be mature as a student, he realised that the freedom of his boyhood was only an illusion. He was actually not free politically, economically or legally to do anything. This brought about in him, a hunger for freedom. But at this stage he thought only about the freedom for himself.
Then, in his hunt for personal freedom he finally realised that it was not only him who was bound by the social system of apartheid, but the people around him were also tied in the same chains. The freedom of all blacks was curtailed. His desire of personal freedom then changed into the hunger of freedom for everyone.
CBSE English - Chapter 2 - Long Walk to Freedom - Page 24 - Q5
5. How did Mandela’s ‘hunger for freedom’ change his life?
Ans. The hunger for freedom of his people to live their lives with dignity and self-respect changed Mandela’s life so much that he transformed from a frightened young man into a bold one; from someone who drove a law-abiding attorney to a criminal; from a family-loving husband into a man without a home and from a life-loving man to a someone who lived like a monk.
In an attempt to serve his people, Mandela also found that he was prevented from fulfilling his obligations as a son, a brother, a father and a husband.
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight - Page 36 - Q 1
1. Why was the young seagull afraid to fly? Do you think all young birds are afraid to make their first flight, or are some birds more timid than others? Do you think a human baby also finds it a challenge to take its first steps?
Ans. The young seagull was not confident enough for his wings to support his flight. So it feared of falling down and hurting himself in an attempt to fly.
Yes, the condition is the same for all young birds. But they overcome this fear by their self confidence. And yes, even for a human baby, the first steps are always a challenge. It takes a lot of courage and curiosity to be confident of your timid legs to support the balance.
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight - Page 36 - Q 2
2. “The sight of the food maddened him.” What does this suggest? What compelled the young seagull to finally fly?
Ans. The seagull was hungry for a long time and was and so the mere sight of food, made his hunger even more uncontrollable. The young seagull’s mother knew that he could fly only if he tried. The biggest fear in him was to take the first step. So she tried to invoke him in order to make him jump over the brink.
We all have to eat to live. So the fright of the young seagull of hurting himself became too timid in front of his hunger and he could not just comprehend his steps towards the brink. It was when he was falling down his natural instincts made his wings flap subconsciously and he saw that he could fly. It was just a sudden reaction towards danger. Just for example if we touch a hot object unknowingly, we simply draw back our hand quickly, even without thinking anything. It’s in our natural instincts to work towards our safety. Similarly, the seagull started flapping his wings when he started to fall down and feared death. But once this happened, he became certain about his capabilities and grew enough self confidence to fly consciously.
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight - Page 36 - Q 3
3. “They were beckoning to him, calling shrilly.” Why did the seagull’s father and mother threaten him and cajole him to fly?
Ans. The young seagull’s parents were concerned about him. They knew that they could not feed him forever, but he had to learn himself to fly and hunt for food. Specially, in seagull family, the children always fly away from their parents to make their own living. And since the young seagull was too afraid to fly, they tried all tactics to make him try for it. They beckoned him, then cajoled, even threatened him following the carrot and stick policy.
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight - Page 36 - Q 4
4. Have you ever had a similar experience, where your parents encouraged you to do something that you were too scared to try? Discuss this in pairs or groups.
Ans. The best example to this can be the first time we start riding a bicycle. We are just too afraid of falling. But once we get going there is no looking back. Perhaps in most of our cases it’s our parents who taught us to ride. They initially give support from behind and then slowly without letting us know, left us for a go.
CBSE 10th English - Chap 3 - Two Stories about Flying - I. His First Flight - Page 36 - Q 5
5. In the case of a bird flying, it seems a natural act, and a foregone conclusion that it should succeed. In the examples you have given in answer to the previous question, was your success guaranteed, or was it important for you to try, regardless of a possibility of failure?
Ans. It’s always important to try on something. The possibility of success is always there if we keep learning from our mistakes and have enough self confidence. This is perhaps not only in one example like riding a bicycle but in every aspect of our life to grow independent. Learning is important and the most difficult part in any venture is to take the initiative. We fear failure so much that many times it prevents us from trying. But we must remember that great deeds are done only by people who take chances and it’s their self confidence which keeps them trying regardless of the possibilities of failure.
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane - Page 40 - Q 1
1. “I’ll take the risk.” What is the risk? Why does the narrator take it?
Ans. The risk was to fly through the storm. The narrator was on his way home, in his Dakota, when he suddenly saw huge storm clouds. He didn’t have sufficient fuel to fly around them to the north or south, so he had only two options with him. Either go back to Paris or fly through the storm, risking his life. But the narrator was going home after a long time and so the crave for delicious home food and the urge for meeting his loved ones made him taking the risk to fly through the storm.
A strong storm can be very dangerous, specially, for a small aeroplane like Dakota.
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane - Page 40 - Q 2
2. Describe the narrator’s experience as he flew the aeroplane into the storm.
Ans. The plane twisted and turned in the storm. The instrument panel was not working. The narrator was not sure about his location and direction. This must have been a fearsome experience.
Then the narrator saw a black aeroplane flying besides his plane. The pilot of another plane waved and asked him to follow him. He proved out to be like an angel to the narrator, as following this unknown plane, he could come out of the storm.
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane - Page 40 - Q 3
3. Why does the narrator say, “I landed and was not sorry to walk away from the old Dakota…”?
Ans. Dakota is a very old model of personal aeroplanes. And on the airport, it would have been similar to parking an old, tattered bicycle among a queue of modern motor bikes. People don’t feel elated while commuting by them. So more often than not, a pilot coming out of an old Dakota always feels sorry for having to fly such an old and rickety model.
But in this story as the pilot weathered the storm and landed safely so he was more than happy to come out from the old Dakota.
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane - Page 40 - Q 4
4. What made the woman in the control centre look at the narrator strangely?
Ans. The woman there was quite sure that there was only one plane in the vicinity of the control centre which was the narrator’s Dakota. She had confirmed it on the radar, so when the narrator asked her about the other aeroplane, she looked at the narrator disbelievingly.
CBSE 10th English - Chap 3 - Two Stories about Flying - II. Black Aeroplane - Page 40 - Q 5
5. Who do you think helped the narrator to reach safely? Discuss this among yourselves and give reasons for your answer.
Ans. The story is ended leaving the readers to guess who the helper was. This could be the narrator’s self belief or confidence with which he dared to enter the storm. Since the radar showed no signs of any other plane to be present there then, it is sure that no plane was there in reality. The author was so eager to reach home that he dared to challenge the storm. But when his compass and radio stopped working, his mind would have brought about an illusion of this black aeroplane in front of him. This kept his hopes alive and let his faith in the decision to enter the storm still correct.
This illusion theory can be given some validity by the way in which the narrator describes the black aeroplane. We don’t normally see a black aeroplane, and that too the narrator could see it among black clouds. Then it was flying without lights on its wings. And normally, with the speed aeroplanes fly, it is hardly possible for two planes to come so close thst the narrator could see the other pilot’s face.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 1
1. Was Anne right when she said that the world would not be interested in the musings of a thirteen-year-old girl?
Ans. No, Anne was proved to be wrong, as this original Dutch work has been translated into many languages and became one of the world’s most widely read books. There have also been several films, television and theatrical productions, and even an opera, based on her diary's contents.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 2
2. There are some examples of diary or journal entries in the ‘Before You Read’ section. Compare these with what Anne writes in her diary. What language was the diary originally written in? In what way is Anne’s diary different?
Ans. Anne wrote the typical diary entries. The one entry that is given is dated 20th June, 1942 in which she describes about the anxiety of her classmates when their results are about to be published. She also 'tells her diary's about the comical incidences which took place in her Maths class involving her.
The original language in which the diary was written was Dutch.
Anne's diary is different in the aspect that she recalls some incidences from past which didn't happen on 20th June, 1942. Normally, one entry in a diary reads the incidents that happened on that particular day. But this can be understood from the fact that the diary's entries started from 12th June, 1942. So, the incidences previous to this date had to be recalled; specially, when the context was that Anne is afraid of her result in Maths. Another different aspect of her diary is marked by the fact that Anne doesn't consider her diary as a dead object, but she makes it her friend and names it as Kitty.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 3
3. Why does Anne need to give a brief sketch about her family? Does she treat ‘Kitty’ as an insider or an outsider?
Ans. Kitty was a new true friend for Anne. She says that she never shared her personal life with any of her friends, but since, with Kitty, there was this relief that she didn't understand her words, she confided with her. So, she starts with giving a brief sketch about her family.
She obviously treats Kitty as an insider. This can be concluded by the fact that she never had any true friend before, to share her feelings. But she does this with Kitty.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 4
4. How does Anne feel about her father, her grandmother, Mrs Kuperus and Mr Keesing? What do these tell you about her?
Ans. Anne felt that her father was the most adorable man she had ever seen. Her grandmother too, was very close to her and after her death; Anne still remembered and loved her. She even dedicated her birthday that year to her grandma.
Mrs. Kuperus was her teacher in sixth form and the headmistress. She was even so close to her as she says at the time of leaving the school, both, Mrs. Kuperus and she was in tears.
Mr. Keesing was her Maths teacher, but he was a little annoyed with her because she kept talking in his classes and was finally forced to give her extra homework. But he too, finally had to change his attitude, at her great wit.
All this tells us that Anne was a very adorable girl. She was loved by everyone. She even had a very good rapport with all her teachers, which means that she was quite intelligent and was a good student.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 5
5. What does Anne write in her first essay?
Ans. Anne was assigned to write three pages on the topic "chatterbox", as punishment for keep talking in her Maths class. She could have easily rambled on keeping big gaps between words to finish off that assignment, but she was quite witty and decided to come up with convincing arguments to prove the necessity of talking.
In her essay, she argued that talking is a student’s trait but then she would do her best to keep it under control. She also tried to convey that that it was impossible for her to fully cure herself of the habit because her mother talked as much as she did, if not more; and there’s not much one can do about inherited traits.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 6
6. Anne says teachers are most unpredictable. Is Mr. Keesing unpredictable? How?
Ans. Mr. Keesing was surely very unpredictable because at one instance he was too annoyed at her and the other, he laughed his heart out at her arguments. Then after giving her the second assignment for she still kept talking, he suddenly didn't say anything for two whole lessons. But he again got too annoyed in his third lesson and gave her another assignment.
It was finally Anne's wit which made him change his attitude towards her talking in the class.
CBSE 10th English - Chap 4 - From the Diary of Anne Frank - Page 54 - Q 7
7. What do these statements tell you about Anne Frank as a person?
(i) We don’t seem to be able to get any closer, and that’s the problem. Maybe it’s my fault that we don’t confide in each other.
(ii) I don’t want to jot down the facts in this diary the way most people would, but I want the diary to be my friend.
(iii) Margot went to Holland in December, and I followed in February, when I was plunked down on the table as a birthday present for Margot.
(iv) If you ask me, there are so many dummies that about a quarter of the class should be kept back, but teachers are the most unpredictable creatures on earth.
(v) Anyone could ramble on and leave big spaces between the words, but the trick was to come up with convincing arguments to prove the necessity of talking.
(i) "We don’t seem to be able to get any closer, and that’s the problem. Maybe it’s my fault that we don’t confide in each other."
Ans. This line indicates that Anne was a bit conservative about her feelings and possessions. (She certainly was not an introvert as she was called a chatterbox.) But then she doesn't blame it to anyone else, but takes it as her own fault to not confide with anyone. This shows the strong character she possessed.
(ii) "I don’t want to jot down the facts in this diary the way most people would, but I want the diary to be my friend."
Ans. She was quite innovative in the way her approach. This was also proved when she was given her first punishment to write an essay on chatterbox. Instead of rambling, she chose to argue why she needed to talk.
The above line also suggests that she felt lonely in the absence of a true friend. A little girl, just into her teens, didn't have a close friend; must have been sad. She even missed her grandma. So finally chose to write a diary.
(iii) "Margot went to Holland in December, and I followed in February, when I was plunked down on the table as a birthday present for Margot."
Ans. This line somewhere seems to give a feeling that Anne wanted to be in Germany. The way she uses the words like ‘plunked down’ and calls herself as just a birthday present for her sister, it seems she had in her, this curbed feeling of discontent for not spending a good time in her native land. Though in her early teens, this diary entry has incidences suggesting that she was a very confident and independent girl. She didn’t like other’s opinion forced on her. And that may also be a cause why she never had a true friend in her life.
(iv) "If you ask me, there are so many dummies that about a quarter of the class should be kept back, but teachers are the most unpredictable creatures on earth."
Ans. This line shows a proud aspect of Anne's character. And may give a clue why she lacked a true friend. Sure, there always are all types of students in any class, but Anne had this feeling of superiority over them. In fact it’s very common in all human beings, and she was no different. We have our own ego which prevents us from making everyone our friend.
The latter half of the sentence shows the childish nature of a little kid. When it comes to results, we never tend to be sure of our teachers, specially, when somebody is annoyed from us.
(v) "Anyone could ramble on and leave big spaces between the words, but the trick was to come up with convincing arguments to prove the necessity of talking."
Ans. This was just too witty and a perfect example of 'never let go' attitude. The essay was a punishment for Anne and she was supposed to take it seriously; not to repeat her mistake again. But she handled it very confidently, and in the other way round, what most students would have done. She still argued that why was it so necessary for her to talk?
This shows that how she was, so different from others and so innovative. She also didn’t like to change herself according to others’ wishes.
CBSE 10th English - Chap 5 - The Hundred Dresses–I
CBSE 10th English - Chap 5 - The Hundred Dresses–I - Page 70 - Q 1
1. How is Wanda seen as different by the other girls? How do they treat her?
Ans. Wanda was natively a Polish girl. So her last name sounded very strange to other American students. It’s something similar to what we feel, when we hear a Chinese or Japanese name. So, the other girls made fun of her. And moreover since she was poor, she wore the same simple blue dress everyday to school. So other girls also teased her by asking how many dresses she had? But when she boldly used her fancy to say that she had a hundred of them, others got another point to make fun by asking her to describe about those dresses and her shoes in her closet because they always knew that what she boasted of was surely not true.
CBSE 10th English - Chap 5 - The Hundred Dresses–I - Page 70 - Q 2
2. How does Wanda feel about the dresses game? Why does she say that she has a hundred dresses?
Ans. Nobody likes being teased about their appearance or name. So for a little girl like Wanda, it would have been very hurting as well. She started ignoring everyone. Solitude spread all around her and she started sitting in the corner seat where there was most scuffling of feet, most roars of laughter when anything funny was said, and most mud and dirt on the floor, just to avoid others.
Wanda always knew that others were making fun of her. So she tried to boldly face everyone and then ignored these pranks by talking about her possession of the hundred dresses. This was nothing other than her fancy. We should not forget that she was still a little girl. So she too would have wished to have many dresses. But she was well aware of her family’s financial situations. She had matured a lot in that early age itself.
CBSE 10th English - Chap 5 - The Hundred Dresses–I - Page 70 - Q 3
3. Why does Maddie stand by and not do anything? How is she different from Peggy? (Was Peggy’s friendship important to Maddie? Why? Which lines in the text tell you this?)
Ans. Maddie was poor herself. So she never liked Peggy, teasing Wanda, in the manner she did. But she was afraid that if she intervened or tried to stop Peggy, she might become the new target for Peggy and the girls.
She was quite different from Peggy, because she was not in favour of teasing Wanda. But Peggy never accepted her mistake, giving some vague arguments in support of her behavior towards Wanda.
But yes, Peggy’s friendship was very important to Maddie because Peggy was her best friend and the best liked girl in the whole room. Moreover, she even wore Peggy’s old dresses.
The lines which tell us this include -
(i) She wished Peggy would stop teasing Wanda Petronski.
(ii) She wished she had the nerve to write Peggy a note, because she knew she never would have the courage to speak right out to Peggy, to say, “Hey, Peg, let’s stop asking Wanda how many dresses she has.”
(iii) Peggy might ask her where she got the dress that she had on, and Maddie would have to say it was one of Peggy’s old ones that Maddie’s mother had tried to disguise with new trimmings so no one in Room Thirteen would recognise it.
(iv) She was Peggy’s best friend, and Peggy was the best-liked girl in the whole room.
CBSE 10th English - Chap 5 - The Hundred Dresses–I - Page 70 - Q 4
4. What does Miss Mason think of Wanda’s drawings? What do the children think of them? How do you know?
Ans. Miss Mason was very happy and proud of Wanda. She found each of her designs very different and beautiful.
Even the children admired those drawings from Wanda. We can say this because they applauded at the announcement of the winner. They gasped with admiration and the boys whistled at them. Even someone like Peggy admitted that Wanda’s drawings were far better than her own.
CBSE 10th English - Chap 6 - The Hundred Dresses–II
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 1
1. Why do you think Wanda’s family moved to a different city? Do you think life there was going to be different for their family?
Ans. Wanda’s father was very perturbed by the fact that his children were the topic of fun for other students, as their named sound funny to others. He was even more angry with the school management which did nothing to stop that. So it became unbearable for him to see his daughter slowly being clutched into solitude and he decided to move to a bigger city with his family.
Wanda came from a poor family and their life could not change anyway by moving into a different city. The only thing was that a bigger city would have more population and more people like them with ‘funny’ names. People there would be so busy with their work that they would hardly notice anyone’s name.
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 2
2. Maddie thought her silence was as bad as Peggy’s teasing. Was she right?
Ans. Maddie was very much correct with her guilt. It’s a common saying that it’s a bigger crime to be a mook spectator to crime. It’s the moral duty of everyone to stop any kind of injustice.
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 3
3. Peggy says, “I never thought she had the sense to know we were making fun of her anyway. I thought she was too dumb. And gee, look how she candraw!” What led Peggy to believe that Wanda was dumb? Did she change her opinion later?
Ans. Peggy thought of Wanda as dumb because whenever she and other girls asked her about her possessions, she said a certain lie and then tried to ignore everything.
Peggy did change her opinion about Wanda after she saw her excellent drawing. She was astonished at her talent and admitted that Wanda was far better an artist than her.
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 4
4. What important decision did Maddie make? Why did she have to think hard to do so?
Ans. The important decision was to stand against any injustice thereafter, whatever result she might have to bear as a consequence. She thought so hard to do so because she feared that trying to protest against making fun of Wanda would make her the next victim to all those teasing. Then Peggy was her best friend too and she didn’t want to loose her friendship. So it was difficult to ask her to stop doing something.
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 5
5. Why do you think Wanda gave Maddie and Peggy the drawings of the dresses? Why are they surprised?
Ans. Although after such bad treatment, Wanda never kept any malice against the girls who teased her. And it was mostly Peggy who asked her about her dresses. Maddie being Peg’s best friend always supported her. So, when she actually made those drawings she did that with Peggy and Maddie in mind. So she dedicated it to them.
Peggy and Wanda were surprised because they never expected any gifts from Wanda after all that fun they made of her.
CBSE 10th English - Chap 6 - The Hundred Dresses–II - Page 79 - Q 6
6. Do you think Wanda really thought the girls were teasing her? Why or Why not?
Ans. Wanda was always aware that the girls were teasing her. Otherwise she wouldn’t have felt so lonely in school. She could not trust anybody as a friend. And then if she knew nothing then even her father would not have come to know about all these incidences and finally decide to move to a different city.
CBSE 10th English - Chap 7 - Glimpses of India - I. A Baker from Goa
CBSE 10th English - Chap 7 - Glimpses of India - I. A Baker from Goa - Page 88 - Q 1
1. Which of these statements are correct?
(i) The pader was an important person in the village in old times.
(ii) Paders still exist in Goan villages.
(iii) The paders went away with the Portuguese.
(iv) The paders continue to wear a single-piece long frock.
(v) Bread and cakes were an integral part of Goan life in the old days.
(vi) Traditional bread-baking is still a very profitable business.
(vii) Paders and their families starve in the present times.
Ans: i , ii, v
CBSE 10th English - Chap 7 - Glimpses of India - I. A Baker from Goa - Page 88 - Q 2
2. Is bread an important part of Goan life? How do you know this?
Ans: Yes, bread is an important part of Goan life. Marriage gifts are meaningless without the sweet bread known as the bol, just as a party or a feast loses its charm without bread. Not enough can be said to show how important a baker can be for a
village. The lady of the house must prepare
sandwiches on the occasion of her daughter’s
engagement. Cakes and bolinhas are a must for
Christmas as well as other festivals. Thus, the
presence of the baker’s furnace in the village is
absolutely essential.
CBSE 10th English - Chap 7 - Glimpses of India - I. A Baker from Goa - Page 88 - Q 3
3. Tick the right answer. What is the tone of the author when he says the following?
(i) The thud and the jingle of the traditional baker’s bamboo can still be
heard in some places. (nostalgic, hopeful, sad)
(ii) Maybe the father is not alive but the son still carries on the family
profession. (nostalgic, hopeful, sad)
(iii) I still recall the typical fragrance of those loaves. (nostalgic, hopeful,
naughty)
(iv) The tiger never brushed his teeth. Hot tea could wash and clean up
everything so nicely, after all. (naughty, angry, funny)
(v) Cakes and bolinhas are a must for Christmas as well as other festivals.
(sad, hopeful, matter-of-fact)
(vi) The baker and his family never starved. They always looked happy and
prosperous. (matter-of-fact, hopeful, sad)
Ans: i - nostalgic, ii - hopeful, iii - nostalgic, iv - naughty, v - matter-of-fact, vi - matter-of-fact
CBSE 10th English - Chap 7 - Glimpses of India - II. Coorg
CBSE 10th English - Chap 7 - Glimpses of India - II. Coorg - Page 92 - Q 1
1. Where is Coorg?
Ans: Coorg, or Kodagu, the smallest district of
karnataka, is located midway between Mysore and the coastal town of Mangalore .
CBSE 10th English - Chap 7 - Glimpses of India - II. Coorg - Page 92 - Q 2
2. What is the story about the Kodavu people’s descent?
Ans: The fiercely independent people of Coorg are possibly of Greek or Arabic descent. As one story goes, a part of Alexander’s army moved south along the coast and settled here when return became impractical. These people married amongst the
locals and their culture is apparent in the martial
traditions, marriage and religious rites, which are
distinct from the Hindu mainstream. The theory of
Arab origin draws support from the long, black coat
with an embroidered waist-belt worn by the Kodavus.
Known as kuppia, it resembles the kuffia worn by
the Arabs and the Kurds.
CBSE 10th English - Chap 7 - Glimpses of India - II. Coorg - Page 92 - Q 3
3. What are some of the things you now know about
(i) the people of Coorg?
(ii) the main crop of Coorg?
(iii) the sports it offers to tourists?
(iv) the animals you are likely to see in Coorg?
(v) its distance from Bangalore, and how to get there?
Ans: i - Kodavus are brave and fiercely independent people. They are possibly descendent of Greek or Arabic.
ii - Coffee
iii -River rafting, canoeing, rappelling, rock climbing and mountain biking.
iv - Birds, bees and butterflies , Macaques, Malabar squirrels, langurs and slender loris, tree canopy and wild elephants.
v - By Road: There are two routes to Coorg from Bangalore. Both are almost the same distance (around 250-260 km). The route via Mysore is the most frequented one. The other route is via Neelamangal, Kunigal,Chanrayanapatna.
CBSE 10th English - Chap 7 - Glimpses of India - II. Coorg - Page 92 - Q 4
4. Here are six sentences with some words in italics. Find phrases from the text that have the same meaning. (Look in the paragraphs indicated)
(i) During monsoons it rains so heavily that tourists do not visit Coorg. (para 2)
(ii) Some people say that Alexander’s army moved south along the coast and settled there. (para 3)
(iii) The Coorg people are always ready to tell stories of their sons’ and fathers’ valour. (para 4)
(iv) Even people who normally lead an easy and slow life get smitten by the high-energy adventure sports of Coorg. (para 6)
(v) The theory of the Arab origin is supported by the long coat with embroidered waist-belt they wear. (para 3)
(vi) Macaques, Malabar squirrels observe you carefully from the tree canopy.
(para 7)
Ans: i - During the monsoons, it pours enough to keep many visitors away.
ii - As one story goes, a part of Alexander’s army moved south along the coast and settled here when return became impractical.
iii - Coorgi homes have a tradition of hospitality, and they are more than willing to recount numerous
tales of valour related to their sons and fathers.
iv - The most laidback individuals become converts
to the life of high-energy adventure with river rafting, canoeing, rappelling, rock climbing and mountain biking.
v - The theory of Arab origin draws support
from the long, black coat with an embroidered waist-belt worn by the Kodavus.
vi - Macaques, Malabar squirrels, langurs and slender loris keep a watchful eye from the tree canopy.
CBSE 10th English - Chap 7 - Glimpses of India - III. Tea from Assam
CBSE 10th English - Chap 8 - Mijbil the Otter
CBSE 10th English - Chap 9 - Madam Rides the Bus
CBSE 10th English - Chap 10 - The Sermon at Benares
CBSE 10th English - Chap 11 - The Proposal
CBSE 10TH Geography
CBSE Geography - Chapter 1 - Resources and Development
CBSE Geography - Chapter 1 - Resources and Development - Page 12 - Q1
1. Multiple choice questions.
(i) Which one of the following type of resource is iron ore?
(a) Renewable (c) Flow
(b) Biotic (d) Non-renewable
(ii) Under which of the following type of resource can tidal energy be put?
(a) Replenishable (c) Abiotic
(b) Human-made (d) Non-recyclable
(iii) Which one of the following is the main cause of land degradation in Punjab?
(a) Intensive cultivation (c) Over irrigation
(b) Deforestation (d) Overgrazing
(iv) In which one of the following states is terrace cultivation practised?
(a) Punjab (c) Haryana
(b) Plains of Uttar Pradesh (d) Uttaranchal
(v) In which of the following states is black soil found?
(a) Jammu and Kashmir (c) Rajasthan
(b) Gujarat (d) Jharkhand
| 1 (i) | (d) Non-Reneable |
| 1 (ii) | (a) Replenishable |
| 1 (iii) | (c) Over irrigation |
| 1 (iv) | (c) Haryana |
| 1 (v) | (b) Gujarat |
CBSE Geography - Chapter 1 - Resources and Development - Page 13 - Q2
2. Answer the following questions in about 30 words.
(i) Name three states having black soil and the crop which is mainly grown in it.
(ii) What type of soil is found in the river deltas of the eastern coast? Give three main features of this type of soil.
(iii) What steps can be taken to control soil erosion in the hilly areas?
(iv) What are the biotic and abiotic resources? Give some examples.
CBSE Geography - Chapter 1 - Resources and Development - Page 13 - Q3
3. Answer the following questions in about 120 words.
(i) Explain land use pattern in India and why has the land under forest not increased much since 1960-61?
(ii) How have technical and economic development led to more consumption of resources?
warming, ozone layer depletion, environmental pollution and land degradation
CBSE Geography - Chapter 2 - Forest and Wildlife Resources
CBSE Geography - Chapter 2 - Forest and Wildlife Resources - Page 22 - Q1
1. Multiple choice questions.
(i) Which of these statements is not a valid reason for the depletion of flora and fauna?
(a) Agricultural expansion.
(b) Large scale developmental projects.
(c) Grazing and fuel wood collection.
(d) Rapid industrialisation and urbanisation.
(ii) Which of the following conservation strategies do not directly involve community participation?
(a) Joint forest management (c) Chipko Movement
(b) Beej Bachao Andolan (d) Demarcation of Wildlife sanctuaries
| 1 (i) | (a) Agricultural expansion. |
| 1 (ii) | (d) Demarcation of Wildlife sanctuaries |
CBSE Geography - Chapter 2 - Forest and Wildlife Resources - Page 22 - Q2
2. Match the following animals with their category of existence.
Animals/Plants Category of existence
Black buck Extinct
Asiatic elephant Rare
Andaman wild pig Endangered
Himalayan brown bear Vulnerable
Pink head duck Endemic
CBSE Geography - Chapter 2 - Forest and Wildlife Resources - Page 22 - Q3
3. Match the following.
Reserved forests other forests and wastelands belonging to bo government and private individuals and communities
Protected forests forests are regarded as most valuable as far as the conservation of forest and wildlife resources
Unclassed forests forest lands are protected from any further depletion
CBSE Geography - Chapter 2 - Forest and Wildlife Resources - Page 22 - Q4
4. Answer the following questions in about 30 words.
(i) What is biodiversity? Why is biodiversity important for human lives?
(ii) How have human activities affected the depletion of flora and fauna? Explain.
Ans: If you look around, you will be able to find out how we have transformed nature into a resource obtaining directly and indirectly from the forests and wildlife – wood, barks, leaves, rubber, medicines, dyes, food, fuel, fodder, manure, etc. So it is we ourselves who havedepleted our forests and wildlife. The greatest damage inflicted on Indian forests was during the colonial period due to the expansion of the railways, agriculture, commercial and scientific forestry and mining activities. Even after Independence, agricultural expansion continues to be one of the major causes of depletion of forest resources.
CBSE Geography - Chapter 2 - Forest and Wildlife Resources - Page 22 - Q5
5. Answer the following questions in about 120 words.
(i) Describe how communities have conserved and protected forests and wildlife in India?
(ii) Write a note on good practices towards conserving forest and wildlife.
CBSE Geography - Chapter 3 - Water Resources
CBSE Geography - Chapter 3 - Water Resources - P33 - Q1
1. Multiple choice questions.
(i) Based on the information given below classify each of the situations as ‘suffering from water scarcity’ or ‘not suffering from water scarcity’.
(a) Region with high annual rainfall.
(b) Region having high annual rainfall and large population.
(c) Region having high annual rainfall but water is highly polluted.
(d) Region having low rainfall and low population.
(ii) Which one of the following statements is not an argument in favour of multipurpose river projects?
(a) Multi-purpose projects bring water to those areas which suffer from water scarcity.
(b) Multi-purpose projects by regulating water flow helps to control floods.
(c) Multi-purpose projects lead to large scale displacements and loss of livelihood.
(d) Multi-purpose projects generate electricity for our industries and our homes.
(iii) Here are some false statements. Identify the mistakes and rewrite them correctly.
(a) Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources.
(b) Regulating and damming of rivers does not affect the river’s natural flow and its sediment flow.
(c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater water harvesting has gained popularity despite high water availability due to the Rajasthan Canal.
| 1(i) |
suffering from water scarcity’ - c not suffering from water scarcity - a , b , d |
| 1(ii) | (c) Multi-purpose projects lead to large scale displacements and loss of livelihood. |
| 1(iii) |
: (a) Multiplying urban centres with large and dense populations and urban lifestyles have restricted proper utilisation of water resources.
(b) Regulating and damming of rivers affects the river’s natural flow and its sediment flow.
(c) In Gujarat, the Sabarmati basin farmers were agitated when higher prioity was given to water supply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater water harvesting has declined due to high water availability due to the RajasthanCanal.
|
CBSE Geography - Chapter 3 - Water Resources - P33 - Q2
2. Answer the following questions in about 30 words.
(i) Explain how water becomes a renewable resource.
(ii) What is water scarcity and what are its main causes?
(iii) Compare the advantages and disadvantages of multi-purpose river projects.
- irrigation
- electricity generation
- water supply for domestic and industrial uses
- flood control
- recreation
- inland navigation
- fish breeding.
- The dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir.
- the big dams have mostly been unsuccessful in controlling floods at the time of excessive rainfall.
- The multi-purpose projects induced earthquakes, caused waterborne diseases and pests and pollution resulting from excessive use of water.
- Multi-purpose projects lead to large scale displacements and loss of livelihood.
CBSE Geography - Chapter 3 - Water Resources - P33 - Q3
3. Answer the following questions in about 120 words.
(i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water
CBSE Geography - Chapter 4 - Agriculture
CBSE Geography - Chapter 4 - Agriculture - P48 - Q1
1. Multiple choice questions.
(i) Which one of the following describes a system of agriculture where a single
crop is grown on a large area?
(a) Shifting Agriculture
(b) Plantation Agriculture
(c) Horticulture
(d) Intensive Agriculture
(ii) Which one of the following is a rabi crop?
(a) Rice (c) Millets
(b) Gram (d) Cotton
(iii) Which one of the following is a leguminous crop?
(a) Pulses (c) Millets
(b) Jawar (d) Sesamum
(iv) Which one of the following is announced by the government in support of a crop?
(a) Maximum support price
(b) Minimum support price
(c) Moderate support price
(d) Influential support price
| 1 (i) | (b) Plantation Agriculture |
| 1 (ii) | (b) Gram |
| 1 (iii) | (a) Pulses |
| 1 (iv) | (b) Minimum support price |
CBSE Geography - Chapter 4 - Agriculture - P48 - Q2
Answer the following questions in 30 words.
(i) Name one important beverage crop and specify the geographical conditions required for its growth.
(ii) Name one staple crop of India and the regions where it is produced.
(iii) Enlist the various institutional reform programmes introduced by the government in the interest of farmers.
(iv) The land under cultivation has got reduced day by day. Can you imagine its consequences?
CBSE Geography - Chapter 4 - Agriculture - P48 - Q3
3. Answer the following questions in about 120 words.
(i) Suggest the initiative taken by the government to ensure the increase in agricultural production.
(ii) How did the partition of the country in 1947 affect the jute industry?
(iii) Describe the impact of globalisation on Indian agriculture.
(iv) Describe the geographical conditions required for the growth of rice
CBSE Geography - Chapter 5 - Minerals and Energy Resources
CBSE Geography - Chapter 5 - Minerals and Energy Resources - P63 - Q1
1. Multiple choice questions.
(i) Which one of the following minerals is formed by decomposition of rocks, leaving a residual mass of weathered material?
(a) coal (b) bauxite (c) gold (d) zinc
(ii) Koderma, in Jharkhand is the leading producer of which one of the following minerals?
(a) bauxite (b) mica (c) iron ore (d) copper
(iii) Minerals are deposited and accumulated in the stratas of which of the following rocks?
(a) sedimentary rocks (c) igneous rocks
(b) metamorphic rocks (d) none of the above
(iv) Which one of the following minerals is contained in the Monazite sand?
(a) oil (b) uranium (c) thorium (d) coal
| 1 (i) | (a) coal |
| 1 (ii) | (b) mica |
| 1 (iii) | (a) sedimentary rocks |
| 1 (iv) | (c) thorium |
CBSE Geography - Chapter 5 - Minerals and Energy Resources - P64 - Q2
2. Answer the following questions in about 30 words.
(i) Distinguish between the following in not more than 30 words.
(a) ferrous and non-ferrous minerals
(b) conventional and non-conventional sources of energy
(ii) What is a mineral?
(iii) How are minerals formed in igneous and metamorphic rocks?
(iv) Why do we need to conserve mineral resources ?
CBSE Geography - Chapter 5 - Minerals and Energy Resources - P64 - Q3
3. Answer the following questions in about 120 words.
(i) Describe the distribution of coal in India.
(ii) Why do you think that solar energy has a bright future in India?
CBSE Geography - Chapter 6 - Manufacturing Industries
CBSE Geography - Chapter 6 - Manufacturing Industries - P79 - Q1
1. Multiple choice questions.
(i) Which one of the following industries uses limestone as a raw material.
(a) Aluminium (b) Cement (c) Sugar (d) Jute
(ii) Which one of the following agencies markets steel for the public sector plants?
(a) HAIL (b) SAIL (c) TATA Steel (d) MNCC
(iii) Which one of the following industries uses bauxite as a raw material?
(a) Aluminium (b) Cement (c) Jute (d) Steel
(iv) Which one of the following industries manufactures telephones, computer, etc.
(a) Steel (c) Aluminium
(b) Electronic (d) Information Technology
| 1 (i) | (b) Cement |
| 1 (ii) | (b) SAIL |
| 1 (iii) | (a) Aluminium |
| 1 (iv) | (b) Electronic |
CBSE Geography - Chapter 6 - Manufacturing Industries - P79 - Q2
2. Answer the following briefly in not more than 30 words.
(i) What is manufacturing?
(ii) Name any three physical factors for the location of the industry.
(iii) Name any three human factors for the location of an industry.
(iv) What are basic industries? Give an example.
(v) Name the important raw materials used in the manufacturing of cement?
- availability of raw material
- power
- land
- labour
- capital
- market
CBSE Geography - Chapter 6 - Manufacturing Industries - P79 - Q3
3. Write the answers of the following questions in 120 words.
(i) How are integrated steel plants different from mini steel plants? What problems does the industry face? What recent developments have led to a rise in the production capacity?
(ii) How do industries pollute the environment?
(iii) Discuss the steps to be taken to minimise environmental degradation by industry?
CBSE Geography - Chapter 7 - Lifelines of National Economy
CBSE 10TH History
CBSE 10TH Maths
Maths Syllabus 2010 - CBSE X
Maths Course Structure
CLASS X
One Paper Time : 3 Hours Marks : 80
UNITS MARKS
I. NUMBER SYSTEMS 04
II. ALGEBRA 20
III. TRIGONOMETRY 12
IV. COORDINATE GEOMETRY 08
V. GEOMETRY 16
VI. MENSURATION 10
VII. STATISTICS AND PROBABILITY 10
TOTAL 80
UNIT I : NUMBER SYSTEMS
1. REAL NUMBERS (15) Periods
Euclid's division lemma, Fundamental Theorem of Arithmetic - statements after reviewing work done earlier
and after illustrating and motivating through examples, Proofs of results - irrationality of 
decimal
expansions of rational numbers in terms of terminating/non-terminating recurring decimals.
UNIT II : ALGEBRA
1. POLYNOMIALS (6) Periods
Zeros of a polynomial. Relationship between zeros and coefficients of a polynomial with particular reference
to quadratic polynomials. Statement and simple problems on division algorithm for polynomials with real
coefficients.
2. PAIR OF LINEAR EQUATIONS IN TWO VARIABLES (15) Periods
Pair of linear equations in two variables. Geometric representation of different possibilities of solutions/
inconsistency.
Algebraic conditions for number of solutions. Solution of pair of linear equations in two variables algebraically
- by substitution, by elimination and by cross multiplication. Simple situational problems must be included.
Simple problems on equations reducible to linear equations may be included.
3. QUADRATIC EQUATIONS (15) Periods
Standard form of a quadratic equation ax2 + bx + c = 0, (a ≠ 0). Solution of the quadratic equations
(only real roots) by factorization and by completing the square, i.e. by using quadratic formula. Relationship
between discriminant and nature of roots.
Problems related to day to day activities to be incorporated.
4. ARITHMETIC PROGRESSIONS (8) Periods
Motivation for studying AP. Derivation of standard results of finding the nth term and sum of first n terms.
UNIT III : TRIGONOMETRY
1. INTRODUCTION TO TRIGONOMETRY (12) Periods
Trigonometric ratios of an acute angle of a right-angled triangle. Proof of their existence (well defined);
motivate the ratios, whichever are defined at 0o & 90o. Values (with proofs) of the trigonometric ratios of
30o, 45o & 60o. Relationships between the ratios.
2. TRIGONOMETRIC IDENTITIES (16) Periods
Proof and applications of the identity sin2 A + cos2 A = 1. Only simple identities to be given. Trigonometric
ratios of complementary angles.
3. HEIGHTS AND DISTANCES (8) Periods
Simple and believable problems on heights and distances. Problems should not involve more than two right
triangles. Angles of elevation / depression should be only 30o, 45o, 60o.
UNIT IV : COORDINATE GEOMETRY
1. LINES (In two-dimensions) (15) Periods
Review the concepts of coordinate geometry done earlier including graphs of linear equations. Awareness of
geometrical representation of quadratic polynomials. Distance between two points and section formula
(internal). Area of a triangle.
UNIT V : GEOMETRY
1. TRIANGLES (15) Periods
Definitions, examples, counter examples of similar triangles.
1. (Prove) If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct
points, the other two sides are divided in the same ratio.
2. (Motivate) If a line divides two sides of a triangle in the same ratio, the line is parallel to the third side.
63
3. (Motivate) If in two triangles, the corresponding angles are equal, their corresponding sides are
proportional and the triangles are similar.
4. (Motivate) If the corresponding sides of two triangles are proportional, their corresponding angles are
equal and the two triangles are similar.
5. (Motivate) If one angle of a triangle is equal to one angle of another triangle and the sides including
these angles are proportional, the two triangles are similar.
6. (Motivate) If a perpendicular is drawn from the vertex of the right angle of a right triangle to the
hypotenuse, the triangles on each side of the perpendicular are similar to the whole triangle and to each
other.
7. (Prove) The ratio of the areas of two similar triangles is equal to the ratio of the squares on their
corresponding sides.
8. (Prove) In a right triangle, the square on the hypotenuse is equal to the sum of the squares on the other
two sides.
9. (Prove) In a triangle, if the square on one side is equal to sum of the squares on the other two sides, the
angles opposite to the first side is a right traingle.
2. CIRCLES (8) Periods
Tangents to a circle motivated by chords drawn from points coming closer and closer to the point.
1. (Prove) The tangent at any point of a circle is perpendicular to the radius through the point of contact.
2. (Prove) The lengths of tangents drawn from an external point to circle are equal.
3. CONSTRUCTIONS (8) Periods
1. Division of a line segment in a given ratio (internally)
2. Tangent to a circle from a point outside it.
3. Construction of a triangle similar to a given triangle.
UNIT VI : MENSURATION
1. AREAS RELATED TO CIRCLES (12) Periods
Motivate the area of a circle; area of sectors and segments of a circle. Problems based on areas and
perimeter / circumference of the above said plane figures. (In calculating area of segment of a circle, problems
should be restricted to central angle of 60o, 90o & 120o only. Plane figures involving triangles, simple
quadrilaterals and circle should be taken.)
2. SURFACE AREAS AND VOLUMES (12) Periods
(i) Problems on finding surface areas and volumes of combinations of any two of the following: cubes,
cuboids, spheres, hemispheres and right circular cylinders/cones. Frustum of a cone.
(ii) Problems involving converting one type of metallic solid into another and other mixed problems. (Problems
with combination of not more than two different solids be taken.)
UNIT VII : STATISTICS AND PROBABILITY
1. STATISTICS (15) Periods
Mean, median and mode of grouped data (bimodal situation to be avoided). Cumulative frequency graph.
2. PROBABILITY (10) Periods
Classical definition of probability. Connection with probability as given in Class IX. Simple problems on
single events, not using set notation.
INTERNAL ASSESSMENT 20 Marks
Evaluation of activities 10 Marks
Project Work 05 Marks
Continuous Evaluation 05 Marks
RECOMMENDED BOOKS
1. Mathematics - Textbook for class IX - NCERT Publication
2. Mathematics - Textbook for class X - NCERT Publication
3. Guidelines for Mathematics Laboratory in Schools, class IX- CBSE Publication
4. Guidelines for Mathematics Laboratory in Schools, class X - CBSE Publication
CBSE 10th Maths Chap 1 - Real Numbers
Chapter Summary
1. Euclid’s division lemma :
Given positive integers a and b, there exist whole numbers q and r satisfying a = bq + r, 0 ≤ r < b.
2. Euclid’s division algorithm : This is based on Euclid’s division lemma. According to this, the HCF of any two positive integers a and b, with a > b, is obtained as follows:
Step 1 : Apply the division lemma to find q and r where a = bq + r, 0 ≤ r < b.
Step 2 : If r = 0, the HCF is b. If r ≠ 0, apply Euclid’s lemma to b and r.
Step 3 : Continue the process till the remainder is zero. The divisor at this stage will be
HCF (a, b). Also, HCF(a, b) = HCF(b, r).
3. The Fundamental Theorem of Arithmetic :
Every composite number can be expressed (factorised) as a product of primes, and this factorisation is unique, apart from the order in which the prime factors occur.
4. If p is a prime and p divides a2, then p divides q, where a is a positive integer.
5. To prove that 2, 3 are irrationals.
6. Let x be a rational number whose decimal expansion terminates. Then we can express x in the form p
q , where p and q are coprime, and the prime factorisation of q is of the form 2n5m, where n, m are non-negative integers.
7. Let x = p/q be a rational number, such that the prime factorisation of q is of the form 2n5m,where n, m are non-negative integers. Then x has a decimal expansion which terminates.
8. Let x = p/q be a rational number, such that the prime factorisation of q is not of the form 2n 5m, where n, m are non-negative integers. Then x has a decimal expansion which isnon-terminating repeating (recurring).
NCERT Book Solutions
CBSE 10TH Maths Chap 1 Ex 1.1 Q1
1. Use Euclid’s division algorithm to find the HCF of :
(i) 135 and 225
(ii) 196 and 38220
(iii) 867 and 255
Default Answer
(i) 45
CBSE 10TH Maths Chap 1 Ex 1.1 Q2
2. Show that any positive odd integer is of the form 6q + 1, or 6q + 3, or 6q + 5, where q is some integer.
CBSE 10TH Maths Chap 1 Ex 1.1 Q3
3. An army contingent of 616 members is to march behind an army band of 32 members in a parade. The two groups are to march in the same number of columns. What is the maximum number of columns in which they can march?
CBSE 10TH Maths Chap 1 Ex 1.1 Q4
4. Use Euclid’s division lemma to show that the square of any positive integer is either of the form 3m or 3m + 1 for some integer m.
CBSE 10TH Maths Chap 1 Ex 1.1 Q5
5. Use Euclid’s division lemma to show that the cube of any positive integer is of the form 9m, 9m + 1 or 9m + 8.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q1
1. Express each number as a product of its prime factors: (i) 140 (ii) 156 (iii) 3825 (iv) 5005 (v) 7429
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q2
2. Find the LCM and HCF of the following pairs of integers and verify that LCM × HCF = product of the two numbers. (i) 26 and 91 (ii) 510 and 92 (iii) 336 and 54
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q2
2. Find the LCM and HCF of the following pairs of integers and verify that LCM × HCF = product of the two numbers. (i) 26 and 91 (ii) 510 and 92 (iii) 336 and 54
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q3
3. Find the LCM and HCF of the following integers by applying the prime factorisation method. (i) 12, 15 and 21 (ii) 17, 23 and 29 (iii) 8, 9 and 25
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q4
4. Given that HCF (306, 657) = 9, find LCM (306, 657).
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q5
5. Check whether 6n can end with the digit 0 for any natural number n.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q6
6. Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.2 Q7
7. There is a circular path around a sports field. Sonia takes 18 minutes to drive one round of the field, while Ravi takes 12 minutes for the same. Suppose they both start at the same point and at the same time, and go in the same direction. After how many minutes will they meet again at the starting point?
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.3 Q1
1. Prove that 5 is irrational.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.3 Q2
2. Prove that 3+2 5 is irrational.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.3 Q3
3. Prove that the following are irrationals : (i) 1 2 (ii) 7 5 (iii) 6+ 2
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.4 Q1
1. Without actually performing the long division, state whether the following rational numbers will have a terminating decimal expansion or a non-terminating repeating decimal expansion: (i) 13 3125 (ii) 17 8 (iii) 64 455 (iv) 15 1600 (v) 29 343 (vi) 3 2 23 2 5 (vii) 2 7 5 129 2 5 7 (viii) 6 15 (ix) 35 50 (x) 77 210
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.4 Q2
2. Write down the decimal expansions of those rational numbers in Question 1 above which have terminating decimal expansions.
CBSE 10TH Maths Real Numbers Chap 1 Ex 1.4 Q3
3. The following real numbers have decimal expansions as given below. In each case, decide whether they are rational or not. If they are rational, and of the form p , q what can you say about the prime factors of q? (i) 43.123456789 (ii) 0.120120012000120000. . . (iii) 43.123456789
CBSE 10th Maths Chap 2 - Polynomials
Chapter Summary
1. Polynomials of degrees 1, 2 and 3 are called linear, quadratic and cubic polynomials respectively.
2. A quadratic polynomial in x with real coefficients is of the form ax2 + bx + c, where a, b, c are real numbers with a ≠ 0.
3. The zeroes of a polynomial p(x) are precisely the x-coordinates of the points, where the graph of y = p(x) intersects the x -axis.
4. A quadratic polynomial can have at most 2 zeroes and a cubic polynomial can have at most 3 zeroes.
5. The division algorithm states that given any polynomial p(x) and any non-zero polynomial g(x), there are polynomials q(x) and r(x) such that p(x) = g(x) q(x) + r(x), where r(x) = 0 or degree r(x) < degree g(x).
NCERT Book Solutions
CBSE 10TH Maths Polynomials Chap 2 Ex 2.2 Q1
1. Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients. (i) x2 – 2x – 8 (ii) 4s2 – 4s + 1 (iii) 6x2 – 3 – 7x (iv) 4u2 + 8u (v) t2 – 15 (vi) 3x2 – x – 4
CBSE 10TH Maths Polynomials Chap 2 Ex 2.2 Q2
2. Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively. (i) 1 , 1 4 − (ii) 2 , 1 3 (iii) 0, 5 (iv) 1, 1 (v) 1, 1 4 4 − (vi) 4, 1
CBSE 10TH Maths Polynomials Chap 2 Ex 2.3 Q1
1. Divide the polynomial p(x) by the polynomial g(x) and find the quotient and remainder in each of the following : (i) p(x) = x3 – 3x2 + 5x – 3, g(x) = x2 – 2 (ii) p(x) = x4 – 3x2 + 4x + 5, g(x) = x2 + 1 – x (iii) p(x) = x4 – 5x + 6, g(x) = 2 – x2
CBSE 10TH Maths Polynomials Chap 2 Ex 2.3 Q2
2. Check whether the first polynomial is a factor of the second polynomial by dividing the second polynomial by the first polynomial: (i) t2 – 3, 2t4 + 3t3 – 2t2 – 9t – 12 (ii) x2 + 3x + 1, 3x4 + 5x3 – 7x2 + 2x + 2 (iii) x3 – 3x + 1, x5 – 4x3 + x2 + 3x + 1
CBSE 10TH Maths Polynomials Chap 2 Ex 2.3 Q3
3. Obtain all other zeroes of 3x4 + 6x3 – 2x2 – 10x – 5, if two of its zeroes are 5and –5 3 3 ⋅
CBSE 10TH Maths Polynomials Chap 2 Ex 2.3 Q4
4. On dividing x3 – 3x2 + x + 2 by a polynomial g(x), the quotient and remainder were x – 2 and –2x + 4, respectively. Find g(x).
CBSE 10TH Maths Polynomials Chap 2 Ex 2.3 Q5
5. Give examples of polynomials p(x), g(x), q(x) and r(x), which satisfy the division algorithm and (i) deg p(x) = deg q(x) (ii) deg q(x) = deg r(x) (iii) deg r(x) = 0
CBSE 10TH Maths Polynomials Chap 2 Ex 2.4 Q1
1. Verify that the numbers given alongside of the cubic polynomials below are their zeroes. Also verify the relationship between the zeroes and the coefficients in each case: (i) 2x3 + x2 – 5x + 2; 1 , 1, – 2 2 (ii) x3 – 4x2 + 5x – 2; 2, 1, 1
CBSE 10TH Maths Polynomials Chap 2 Ex 2.4 Q2
2. Find a cubic polynomial with the sum, sum of the product of its zeroes taken two at a time, and the product of its zeroes as 2, –7, –14 respectively.
CBSE 10TH Maths Polynomials Chap 2 Ex 2.4 Q3
3. If the zeroes of the polynomial x3 – 3x2 + x + 1 are a – b, a, a + b, find a and b.
CBSE 10TH Maths Polynomials Chap 2 Ex 2.4 Q4
4. If two zeroes of the polynomial x4 – 6x3 – 26x2 + 138x – 35 are 2± 3, find other zeroes.
CBSE 10TH Maths Polynomials Chap 2 Ex 2.4 Q5
5. If the polynomial x4 – 6x3 + 16x2 – 25x + 10 is divided by another polynomial x2 – 2x + k, the remainder comes out to be x + a, find k and a.
CBSE 10th Maths Chap 3 - PAIR OF LINEAR EQUATIONS IN TWO VARIABLES
Chapter Summary
1. Two linear equations in the same two variables are called a pair of linear equations in two variables. The most general form of a pair of linear equations is
a1x + b1y + c1 = 0
a2x + b2y + c2 = 0
where a1, a2, b1, b2, c1, c2 are real numbers, such that a12+b12 ≠ 0, a22+b22 ≠ 0.
2. A pair of linear equations in two variables can be represented, and solved, by the:
(i) graphical method
(ii) algebraic method
3. Graphical Method :
The graph of a pair of linear equations in two variables is represented by two lines.
(i) If the lines intersect at a point, then that point gives the unique solution of the two equations. In this case, the pair of equations is consistent.
(ii) If the lines coincide, then there are infinitely many solutions — each point on the line being a solution. In this case, the pair of equations is dependent (consistent).
(iii) If the lines are parallel, then the pair of equations has no solution. In this case, the pair of equations is inconsistent.
4. Algebraic Methods : We have discussed the following methods for finding the solution(s) of a pair of linear equations :
(i) Substitution Method
(ii) Elimination Method
(iii) Cross-multiplication Method
5. There are several situations which can be mathematically represented by two equations that are not linear to start with. But we alter them so that they are reduced to a pair of linear equations.
NCERT Book Solutions
CBSE 10th Maths Chap 4 - Quadratic Equations
CBSE 10th Maths Chap 5 - Arithmetic Progressions
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P99 - Q1
In which of the following situations, does the list of numbers involved make as arithmetic progression and why?
(i) The taxi fare after each km when the fare is Rs 15 for the first km and Rs 8 for each additional km.
(ii) The amount of air present in a cylinder when a vacuum pump removes of the air remaining in the cylinder at a time.
(iii) The cost of digging a well after every metre of digging, when it costs Rs 150 for the first metre and rises by Rs 50 for each subsequent metre.
(iv)The amount of money in the account every year, when Rs 10000 is deposited at compound interest at 8% per annum.
(i) It can be observed that
Taxi fare for 1st km = 15
Taxi fare for first 2 km = 15 + 8 = 23
Taxi fare for first 3 km = 23 + 8 = 31
Taxi fare for first 4 km = 31 + 8 = 39
Clearly 15, 23, 31, 39 … forms an A.P. because every term is 8 more than the preceding term.
(ii) Let the initial volume of air in a cylinder be V lit. In each stroke, the vacuum pump removes of air remaining in the cylinder at a time. In other words, after every stroke, only
part of air will remain.
Therefore, volumes will be
Clearly, it can be observed that the adjacent terms of this series do not have the same difference between them. Therefore, this is not an A.P.
(iii) Cost of digging for first metre = 150
Cost of digging for first 2 metres = 150 + 50 = 200
Cost of digging for first 3 metres = 200 + 50 = 250
Cost of digging for first 4 metres = 250 + 50 = 300
Clearly, 150, 200, 250, 300 … forms an A.P. because every term is 50 more than the preceding term.
(iv) We know that if Rs P is deposited at r% compound interest per annum for n years, our money will be after n years.
Therefore, after every year, our money will be
Clearly, adjacent terms of this series do not have the same difference between them. Therefore, this is not an A.P.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q3
In the following APs find the missing term in the boxes
I. 2,_,26
II._,13,_,3
III.5,_,_,
IV.-4,_,_,_,_,6
V._,38,_,_,_,-22
I. 2,_,26
For this A.P.,
a = 2
a3 = 26
We know that, an = a + (n − 1) d
a3 = 2 + (3 − 1) d
26 = 2 + 2d
24 = 2d
d = 12
a2 = 2 + (2 − 1) 12
= 14
Therefore, 14 is the missing term.
II._,13,_,3
For this A.P.,
a2 = 13 and
a4 = 3
We know that, an = a + (n − 1) d
a2 = a + (2 − 1) d
13 = a + d (I)
a4 = a + (4 − 1) d
3 = a + 3d (II)
On subtracting (I) from (II), we obtain
−10 = 2d
d = −5
From equation (I), we obtain
13 = a + (−5)
a = 18
a3 = 18 + (3 − 1) (−5)
= 18 + 2 (−5) = 18 − 10 = 8
Therefore, the missing terms are 18 and 8 respectively.
III..5,_,_,
For this A.P.
a=5
We know that,
Therefore, the missing terms are and 8 respectively.
IV.-4,_,_,_,_,6
For this A.P.,
a = −4 and
a6 = 6
We know that,
an = a + (n − 1) d
a6 = a + (6 − 1) d
6 = − 4 + 5d
10 = 5d
d = 2
a2 = a + d = − 4 + 2 = −2
a3 = a + 2d = − 4 + 2 (2) = 0
a4 = a + 3d = − 4 + 3 (2) = 2
a5 = a + 4d = − 4 + 4 (2) = 4
Therefore, the missing terms are −2, 0, 2, and 4 respectively.
V._,38,_,_,_,-22
For this A.P.,
a2 = 38
a6 = −22
We know that
an = a + (n − 1) d
a2 = a + (2 − 1) d
38 = a + d (1)
a6 = a + (6 − 1) d
−22 = a + 5d (2)
On subtracting equation (1) from (2), we obtain
− 22 − 38 = 4d
−60 = 4d
d = −15
a = a2 − d = 38 − (−15) = 53
a3 = a + 2d = 53 + 2 (−15) = 23
a4 = a + 3d = 53 + 3 (−15) = 8
a5 = a + 4d = 53 + 4 (−15) = −7
Therefore, the missing terms are 53, 23, 8, and −7 respectively.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P99 - Q2
Write first four terms of the A.P. when the first term a and the common difference d are given as follows
(i) a = 10, d = 10
(ii) a = − 2, d = 0
(iii) a = 4, d = − 3
(iv) a = − 1 d =
(v) a = − 1.25, d = − 0.25
(i) a = 10, d = 10
Let the series be a1, a2, a3, a4, a5 …
a1 = a = 10
a2 = a1 + d = 10 + 10 = 20
a3 = a2 + d = 20 + 10 = 30
a4 = a3 + d = 30 + 10 = 40
a5 = a4 + d = 40 + 10 = 50
Therefore, the series will be 10, 20, 30, 40, 50 …
First four terms of this A.P. will be 10, 20, 30, and 40.
(ii) a = −2, d = 0
Let the series be a1, a2, a3, a4 …
a1 = a = −2
a2 = a1 + d = − 2 + 0 = −2
a3 = a2 + d = − 2 + 0 = −2
a4 = a3 + d = − 2 + 0 = −2
Therefore, the series will be −2, −2, −2, −2 …
First four terms of this A.P. will be −2, −2, −2 and −2.
(iii) a = 4, d = −3
Let the series be a1, a2, a3, a4 …
a1 = a = 4
a2 = a1 + d = 4 − 3 = 1
a3 = a2 + d = 1 − 3 = −2
a4 = a3 + d = − 2 − 3 = −5
Therefore, the series will be 4, 1, −2 −5 …
First four terms of this A.P. will be 4, 1, −2 and −5.
(iv) a = −1, d =
Let the series be a1, a2, a3, a4 …
Clearly, the series will be
First four terms of this A.P. will be
(v) a = −1.25, d = −0.25
Let the series be a1, a2, a3, a4 …
a1 = a = −1.25
a2 = a1 + d = − 1.25 − 0.25 = −1.50
a3 = a2 + d = − 1.50 − 0.25 = −1.75
a4 = a3 + d = − 1.75 − 0.25 = −2.00
Clearly, the series will be 1.25, −1.50, −1.75, −2.00 ……..
First four terms of this A.P. will be −1.25, −1.50, −1.75 and −2.00.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P99 - Q3
For the following A.P.s, write the first term and the common difference.
(i) 3, 1, − 1, − 3 …
(ii) − 5, − 1, 3, 7 …
(iii)
(iv) 0.6, 1.7, 2.8, 3.9
(i) 3, 1, −1, −3 …
Here, first term, a = 3
Common difference, d = Second term − First term
= 1 − 3 = −2
(ii) −5, −1, 3, 7 …
Here, first term, a = −5
Common difference, d = Second term − First term
= (−1) − (−5) = − 1 + 5 = 4
(iii)
Here, first term,
Common difference, d = Second term − First term
(iv) 0.6, 1.7, 2.8, 3.9 …
Here, first term, a = 0.6
Common difference, d = Second term − First term
= 1.7 − 0.6
= 1.1
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P99 - Q4
Which of the following are APs? If they form an A.P. find the common difference d and write three more terms.
(i) 2, 4, 8, 16 …
(ii)
(iii) − 1.2, − 3.2, − 5.2, − 7.2 …
(iv) − 10, − 6, − 2, 2 …
(v)
(vi) 0.2, 0.22, 0.222, 0.2222 ….
(vii) 0, − 4, − 8, − 12 …
(viii)
(ix) 1, 3, 9, 27 …
(x) a, 2a, 3a, 4a …
(xi) a, a2, a3, a4 …
(xii)
(xiii)
(xiv) 12, 32, 52, 72 …
(xv) 12, 52, 72, 73 …
(i) 2, 4, 8, 16 …
It can be observed that
a2 − a1 = 4 − 2 = 2
a3 − a2 = 8 − 4 = 4
a4 − a3 = 16 − 8 = 8
i.e., ak+1− ak is not the same every time. Therefore, the given numbers are not forming an A.P.
(ii)
It can be observed that
i.e., ak+1− ak is same every time.
Therefore, and the given numbers are in A.P.
Three more terms are
(iii) −1.2, −3.2, −5.2, −7.2 …
It can be observed that
a2 − a1 = (−3.2) − (−1.2) = −2
a3 − a2 = (−5.2) − (−3.2) = −2
a4 − a3 = (−7.2) − (−5.2) = −2
i.e., ak+1− ak is same every time. Therefore, d = −2
The given numbers are in A.P.
Three more terms are
a5 = − 7.2 − 2 = −9.2
a6 = − 9.2 − 2 = −11.2
a7 = − 11.2 − 2 = −13.2
(iv) −10, −6, −2, 2 …
It can be observed that
a2 − a1 = (−6) − (−10) = 4
a3 − a2 = (−2) − (−6) = 4
a4 − a3 = (2) − (−2) = 4
i.e., ak+1 − ak is same every time. Therefore, d = 4
The given numbers are in A.P.
Three more terms are
a5 = 2 + 4 = 6
a6 = 6 + 4 = 10
a7 = 10 + 4 = 14
(v)
It can be observed that
i.e., ak+1 − ak is same every time. Therefore,
The given numbers are in A.P.
Three more terms are
(vi) 0.2, 0.22, 0.222, 0.2222 ….
It can be observed that
a2 − a1 = 0.22 − 0.2 = 0.02
a3 − a2 = 0.222 − 0.22 = 0.002
a4 − a3 = 0.2222 − 0.222 = 0.0002
i.e., ak+1 − ak is not the same every time.
Therefore, the given numbers are not in A.P.
(vii) 0, −4, −8, −12 …
It can be observed that
a2 − a1 = (−4) − 0 = −4
a3 − a2 = (−8) − (−4) = −4
a4 − a3 = (−12) − (−8) = −4
i.e., ak+1 − ak is same every time. Therefore, d = −4
The given numbers are in A.P.
Three more terms are
a5 = − 12 − 4 = −16
a6 = − 16 − 4 = −20
a7 = − 20 − 4 = −24
(viii)
It can be observed that
i.e., ak+1 − ak is same every time. Therefore, d = 0
The given numbers are in A.P.
Three more terms are
(ix) 1, 3, 9, 27 …
It can be observed that
a2 − a1 = 3 − 1 = 2
a3 − a2 = 9 − 3 = 6
a4 − a3 = 27 − 9 = 18
i.e., ak+1 − ak is not the same every time.
Therefore, the given numbers are not in A.P.
(x) a, 2a, 3a, 4a …
It can be observed that
a2 − a1 = 2a − a = a
a3 − a2 = 3a − 2a = a
a4 − a3 = 4a − 3a = a
i.e., ak+1 − ak is same every time. Therefore, d = a
The given numbers are in A.P.
Three more terms are
a5 = 4a + a = 5a
a6 = 5a + a = 6a
a7 = 6a + a = 7a
(xi) a, a2, a3, a4 …
It can be observed that
a2 − a1 = a2 − a = a (a − 1)
a3 − a2 = a3 − a2 = a2 (a − 1)
a4 − a3 = a4 − a3 = a3 (a − 1)
i.e., ak+1 − ak is not the same every time.
Therefore, the given numbers are not in A.P.
(xii)
It can be observed that
i.e., ak+1 − ak is same every time.
Therefore, the given numbers are in A.P.
And,
Three more terms are
(xiii)
It can be observed that
i.e., ak+1 − ak is not the same every time.
Therefore, the given numbers are not in A.P.
(xiv) 12, 32, 52, 72 …
Or, 1, 9, 25, 49 …..
It can be observed that
a2 − a1 = 9 − 1 = 8
a3 − a2 = 25 − 9 = 16
a4 − a3 = 49 − 25 = 24
i.e., ak+1 − ak is not the same every time.
Therefore, the given numbers are not in A.P.
(xv) 12, 52, 72, 73 …
Or 1, 25, 49, 73 …
It can be observed that
a2 − a1 = 25 − 1 = 24
a3 − a2 = 49 − 25 = 24
a4 − a3 = 73 − 49 = 24
i.e., ak+1 − ak is same every time.
Therefore, the given numbers are in A.P.
And, d = 24
Three more terms are
a5 = 73+ 24 = 97
a6 = 97 + 24 = 121
a7 = 121 + 24 = 145
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P105 - Q1
Fill in the blanks in the following table, given that a is the first term, d the common difference and an the nth term of the A.P.
|
a |
d |
n |
an |
|
|
I |
7 |
3 |
8 |
…... |
|
II |
− 18 |
….. |
10 |
0 |
|
III |
….. |
− 3 |
18 |
− 5 |
|
IV |
− 18.9 |
2.5 |
….. |
3.6 |
|
V |
3.5 |
0 |
105 |
….. |
I. a = 7, d = 3, n = 8, an = ?
We know that,
For an A.P. an = a + (n − 1) d
= 7 + (8 − 1) 3
= 7 + (7) 3
= 7 + 21 = 28
Hence, an = 28
II. Given that
a = −18, n = 10, an = 0, d = ?
We know that,
an = a + (n − 1) d
0 = − 18 + (10 − 1) d
18 = 9d
Hence, common difference, d = 2
III. Given that
d = −3, n = 18, an = −5
We know that,
an = a + (n − 1) d
−5 = a + (18 − 1) (−3)
−5 = a + (17) (−3)
−5 = a − 51
a = 51 − 5 = 46
Hence, a = 46
IV. a = −18.9, d = 2.5, an = 3.6, n = ?
We know that,
an = a + (n − 1) d
3.6 = − 18.9 + (n − 1) 2.5
3.6 + 18.9 = (n − 1) 2.5
22.5 = (n − 1) 2.5
Hence, n = 10
V. a = 3.5, d = 0, n = 105, an = ?
We know that,
an = a + (n − 1) d
an = 3.5 + (105 − 1) 0
an = 3.5 + 104 × 0
an = 3.5
Hence, an = 3.5
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q2
Choose the correct choice in the following and justify
I. 30th term of the A.P: 10, 7, 4, …, is
A. 97 B. 77 C. − 77 D. − 87
II 11th term of the A.P. is
A. 28 B. 22 C. 3,is D
I. Given that
A.P. 10, 7, 4, …
First term, a = 10
Common difference, d = a2 − a1 = 7 − 10
= −3
We know that, an = a + (n − 1) d
a30 = 10 + (30 − 1) (−3)
a30 = 10 + (29) (−3)
a30 = 10 − 87 = −77
Hence, the correct answer is C.
II. Given that, A.P.
First term a = −3
Common difference, d = a2 − a1
We know that,
Hence, the answer is B.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q4
Which term of the A.P. 3, 8, 13, 18, … is 78?
3, 8, 13, 18, …
For this A.P.,
a = 3
d = a2 − a1 = 8 − 3 = 5
Let nth term of this A.P. be 78.
an = a + (n − 1) d
78 = 3 + (n − 1) 5
75 = (n − 1) 5
(n − 1) = 15
n = 16
Hence, 16th term of this A.P. is 78.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q5
Find the number of terms in each of the following A.P.
I. 7, 13, 19, …, 205
II.18,,13,...,-47
I. 7, 13, 19, …, 205
For this A.P.,
a = 7
d = a2 − a1 = 13 − 7 = 6
Let there are n terms in this A.P.
an = 205
We know that
an = a + (n − 1) d
Therefore, 205 = 7 + (n − 1) 6
198 = (n − 1) 6
33 = (n − 1)
n = 34
Therefore, this given series has 34 terms in it.
II.18,,13,...,-47
For this A.P,
Let there are n terms in this A.P.
Therefore, an = −47 and we know that,
Therefore, this given A.P. has 27 terms in it.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q6
Check whether − 150 is a term of the A.P. 11, 8, 5, 2, …
For this A.P.,
a = 11
d = a2 − a1 = 8 − 11 = −3
Let −150 be the nth term of this A.P.
We know that,
Clearly, n is not an integer.
Therefore, −150 is not a term of this A.P.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q7
Find the 31st term of an A.P. whose 11th term is 38 and the 16th term is 73
Given that,
a11 = 38
a16 = 73
We know that,
an = a + (n − 1) d
a11 = a + (11 − 1) d
38 = a + 10d (1)
Similarly,
a16 = a + (16 − 1) d
73 = a + 15d (2)
On subtracting (1) from (2), we obtain
35 = 5d
d = 7
From equation (1),
38 = a + 10 × (7)
38 − 70 = a
a = −32
a31 = a + (31 − 1) d
= − 32 + 30 (7)
= − 32 + 210
= 178
Hence, 31st term is 178.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q8
An A.P. consists of 50 terms of which 3rd term is 12 and the last term is 106. Find the 29th term
Given that,
a3 = 12
a50 = 106
We know that,
an = a + (n − 1) d
a3 = a + (3 − 1) d
12 = a + 2d (I)
Similarly, a50 = a + (50 − 1) d
106 = a + 49d (II)
On subtracting (I) from (II), we obtain
94 = 47d
d = 2
From equation (I), we obtain
12 = a + 2 (2)
a = 12 − 4 = 8
a29 = a + (29 − 1) d
a29 = 8 + (28)2
a29 = 8 + 56 = 64
Therefore, 29th term is 64.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q9
If the 3rd and the 9th terms of an A.P. are 4 and − 8 respectively. Which term of this A.P. is zero.
Given that,
a3 = 4
a9 = −8
We know that,
an = a + (n − 1) d
a3 = a + (3 − 1) d
4 = a + 2d (I)
a9 = a + (9 − 1) d
−8 = a + 8d (II)
On subtracting equation (I) from (II), we obtain
−12 = 6d
d = −2
From equation (I), we obtain
4 = a + 2 (−2)
4 = a − 4
a = 8
Let nth term of this A.P. be zero.
an = a + (n − 1) d
0 = 8 + (n − 1) (−2)
0 = 8 − 2n + 2
2n = 10
n = 5
Hence, 5th term of this A.P. is 0.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q10
If 17th term of an A.P. exceeds its 10th term by 7. Find the common difference.
We know that,
For an A.P., an = a + (n − 1) d
a17 = a + (17 − 1) d
a17 = a + 16d
Similarly, a10 = a + 9d
It is given that
a17 − a10 = 7
(a + 16d) − (a + 9d) = 7
7d = 7
d = 1
Therefore, the common difference is 1.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q11
Which term of the A.P. 3, 15, 27, 39, … will be 132 more than its 54th term?
Given A.P. is 3, 15, 27, 39, …
a = 3
d = a2 − a1 = 15 − 3 = 12
a54 = a + (54 − 1) d
= 3 + (53) (12)
= 3 + 636 = 639
132 + 639 = 771
We have to find the term of this A.P. which is 771.
Let nth term be 771.
an = a + (n − 1) d
771 = 3 + (n − 1) 12
768 = (n − 1) 12
(n − 1) = 64
n = 65
Therefore, 65th term was 132 more than 54th term.
Alternatively,
Let nth term be 132 more than 54th term.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q12
Two APs have the same common difference. The difference between their 100th term is 100, what is the difference between their 1000th terms?
Let the first term of these A.P.s be a1 and a2 respectively and the common difference of these A.P.s be d.
For first A.P.,
a100 = a1 + (100 − 1) d
= a1 + 99d
a1000 = a1 + (1000 − 1) d
a1000 = a1 + 999d
For second A.P.,
a100 = a2 + (100 − 1) d
= a2 + 99d
a1000 = a2 + (1000 − 1) d
= a2 + 999d
Given that, difference between
100th term of these A.P.s = 100
Therefore, (a1 + 99d) − (a2 + 99d) = 100
a1 − a2 = 100 (1)
Difference between 1000th terms of these A.P.s
(a1 + 999d) − (a2 + 999d) = a1 − a2
From equation (1),
This difference, a1 − a2 = 100
Hence, the difference between 1000th terms of these A.P. will be 100.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q13
How many three digit numbers are divisible by 7
First three-digit number that is divisible by 7 = 105
Next number = 105 + 7 = 112
Therefore, 105, 112, 119, …
All are three digit numbers which are divisible by 7 and thus, all these are terms of an A.P. having first term as 105 and common difference as 7.
The maximum possible three-digit number is 999. When we divide it by 7, the remainder will be 5. Clearly, 999 − 5 = 994 is the maximum possible three-digit number that is divisible by 7.
The series is as follows.
105, 112, 119, …, 994
Let 994 be the nth term of this A.P.
a = 105
d = 7
an = 994
n = ?
an = a + (n − 1) d
994 = 105 + (n − 1) 7
889 = (n − 1) 7
(n − 1) = 127
n = 128
Therefore, 128 three-digit numbers are divisible by 7.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q14
How many multiples of 4 lie between 10 and 250?
First multiple of 4 that is greater than 10 is 12. Next will be 16.
Therefore, 12, 16, 20, 24, …
All these are divisible by 4 and thus, all these are terms of an A.P. with first term as 12 and common difference as 4.
When we divide 250 by 4, the remainder will be 2. Therefore, 250 − 2 = 248 is divisible by 4.
The series is as follows.
12, 16, 20, 24, …, 248
Let 248 be the nth term of this A.P.
Therefore, there are 60 multiples of 4 between 10 and 250.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q15
For what value of n, are the nth terms of two APs 63, 65, 67, and 3, 10, 17, … equal
63, 65, 67, …
a = 63
d = a2 − a1 = 65 − 63 = 2
nth term of this A.P. = an = a + (n − 1) d
an= 63 + (n − 1) 2 = 63 + 2n − 2
an = 61 + 2n (1)
3, 10, 17, …
a = 3
d = a2 − a1 = 10 − 3 = 7
nth term of this A.P. = 3 + (n − 1) 7
an = 3 + 7n − 7
an = 7n − 4 (2)
It is given that, nth term of these A.P.s are equal to each other.
Equating both these equations, we obtain
61 + 2n = 7n − 4
61 + 4 = 5n
5n = 65
n = 13
Therefore, 13th terms of both these A.P.s are equal to each other.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P106 - Q16
Determine the A.P. whose third term is 16 and the 7th term exceeds the 5th term by 12.
=a3 = 16
a + (3 − 1) d = 16
a + 2d = 16 (1)
a7 − a5 = 12
[a+ (7 − 1) d] − [a + (5 − 1) d]= 12
(a + 6d) − (a + 4d) = 12
2d = 12
d = 6
From equation (1), we obtain
a + 2 (6) = 16
a + 12 = 16
a = 4
Therefore, A.P. will be
4, 10, 16, 22, …
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P107 - Q17
Find the 20th term from the last term of the A.P. 3, 8, 13, …, 253
Given A.P. is
3, 8, 13, …, 253
Common difference for this A.P. is 5.
Therefore, this A.P. can be written in reverse order as
253, 248, 243, …, 13, 8, 5
For this A.P.,
a = 253
d = 248 − 253 = −5
n = 20
a20 = a + (20 − 1) d
a20 = 253 + (19) (−5)
a20 = 253 − 95
a = 158
Therefore, 20th term from the last term is 158.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P107 - Q18
The sum of 4th and 8th terms of an A.P. is 24 and the sum of the 6th and 10th terms is 44. Find the first three terms of the A.P.
We know that,
an = a + (n − 1) d
a4 = a + (4 − 1) d
a4 = a + 3d
Similarly,
a8 = a + 7d
a6 = a + 5d
a10 = a + 9d
Given that, a4 + a8 = 24
a + 3d + a + 7d = 24
2a + 10d = 24
a + 5d = 12 (1)
a6 + a10 = 44
a + 5d + a + 9d = 44
2a + 14d = 44
a + 7d = 22 (2)
On subtracting equation (1) from (2), we obtain
2d = 22 − 12
2d = 10
d = 5
From equation (1), we obtain
a + 5d = 12
a + 5 (5) = 12
a + 25 = 12
a = −13
a2 = a + d = − 13 + 5 = −8
a3 = a2 + d = − 8 + 5 = −3
Therefore, the first three terms of this A.P. are −13, −8, and −3.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P107 - Q19
Subba Rao started work in 1995 at an annual salary of Rs 5000 and received an increment of Rs 200 each year. In which year did his income reach Rs 7000?
It can be observed that the incomes that Subba Rao obtained in various years are in A.P. as every year, his salary is increased by Rs 200.
Therefore, the salaries of each year after 1995 are
5000, 5200, 5400, …
Here, a = 5000
d = 200
Let after nth year, his salary be Rs 7000.
Therefore, an = a + (n − 1) d
7000 = 5000 + (n − 1) 200
200(n − 1) = 2000
(n − 1) = 10
n = 11
Therefore, in 11th year, his salary will be Rs 7000.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P107 - Q20
Ramkali saved Rs 5 in the first week of a year and then increased her weekly saving by Rs 1.75. If in the nth week, her week, her weekly savings become Rs 20.75, find n.
Given that,
a = 5
d = 1.75
an = 20.75
n = ?
an = a + (n − 1) d
Hence, n is 10.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P112 - Q1
Find the sum of the following APs.
(i) 2, 7, 12 ,…., to 10 terms.
(ii) − 37, − 33, − 29 ,…, to 12 terms
(iii) 0.6, 1.7, 2.8 ,…….., to 100 terms
(iv) ,………, to 11 terms
(i)2, 7, 12 ,…, to 10 terms
For this A.P.,
a = 2
d = a2 − a1 = 7 − 2 = 5
n = 10
We know that,
(ii)−37, −33, −29 ,…, to 12 terms
For this A.P.,
a = −37
d = a2 − a1 = (−33) − (−37)
= − 33 + 37 = 4
n = 12
We know that,
(iii) 0.6, 1.7, 2.8 ,…, to 100 terms
For this A.P.,
a = 0.6
d = a2 − a1 = 1.7 − 0.6 = 1.1
n = 100
We know that,
(iv),………, to 11 terms
For this A.P.
n = 11
We know that,
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P112 - Q2
Find the sums given below
(i) 7 + + 14 + ………… + 84
(ii) 34 + 32 + 30 + ……….. + 10
(iii) − 5 + (− 8) + (− 11) + ………… + (− 230)
(i) 7 + + 14 + ………… + 84
For this A.P.,
a = 7
l = 84
Let 84 be the nth term of this A.P.
l = a + (n − 1)d
22 = n − 1
n = 23
We know that,
(ii)34 + 32 + 30 + ……….. + 10
For this A.P.,
a = 34
d = a2 − a1 = 32 − 34 = −2
l = 10
Let 10 be the nth term of this A.P.
l = a + (n − 1) d
10 = 34 + (n − 1) (−2)
−24 = (n − 1) (−2)
12 = n − 1
n = 13
(iii)(−5) + (−8) + (−11) + ………… + (−230)
For this A.P.,
a = −5
l = −230
d = a2 − a1 = (−8) − (−5)
= − 8 + 5 = −3
Let −230 be the nth term of this A.P.
l = a + (n − 1)d
−230 = − 5 + (n − 1) (−3)
−225 = (n − 1) (−3)
(n − 1) = 75
n = 76
And,
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P112 - Q3
In an AP
(i) Given a = 5, d = 3, an = 50, find n and Sn.
(ii) Given a = 7, a13 = 35, find d and S13.
(iii) Given a12 = 37, d = 3, find a and S12.
(iv) Given a3 = 15, S10 = 125, find d and a10.
(v) Given d = 5, S9 = 75, find a and a9.
(vi) Given a = 2, d = 8, Sn = 90, find n and an.
(vii) Given a = 8, an = 62, Sn = 210, find n and d.
(viii) Given an = 4, d = 2, Sn = − 14, find n and a.
(ix) Given a = 3, n = 8, S = 192, find d.
(x)Given l = 28, S = 144 and there are total 9 terms. Find a.
(i) Given that, a = 5, d = 3, an = 50
As an = a + (n − 1)d,
∴ 50 = 5 + (n − 1)3
45 = (n − 1)3
15 = n − 1
n = 16
(ii) Given that, a = 7, a13 = 35
As an = a + (n − 1) d,
∴ a13 = a + (13 − 1) d
35 = 7 + 12 d
35 − 7 = 12d
28 = 12d
(iii)Given that, a12 = 37, d = 3
As an = a + (n − 1)d,
a12 = a + (12 − 1)3
37 = a + 33
a = 4
(iv) Given that, a3 = 15, S10 = 125
As an = a + (n − 1)d,
a3 = a + (3 − 1)d
15 = a + 2d (i)
On multiplying equation (1) by 2, we obtain
30 = 2a + 4d (iii)
On subtracting equation (iii) from (ii), we obtain
−5 = 5d
d = −1
From equation (i),
15 = a + 2(−1)
15 = a − 2
a = 17
a10 = a + (10 − 1)d
a10 = 17 + (9) (−1)
a10 = 17 − 9 = 8
(v)Given that, d = 5, S9 = 75
As,
25 = 3(a + 20)
25 = 3a + 60
3a = 25 − 60
an = a + (n − 1)d
a9 = a + (9 − 1) (5)
(vi) Given that, a = 2, d = 8, Sn = 90
As,
90 = n [2 + (n − 1)4]
90 = n [2 + 4n − 4]
90 = n (4n − 2) = 4n2 − 2n
4n2 − 2n − 90 = 0
4n2 − 20n + 18n − 90 = 0
4n (n − 5) + 18 (n − 5) = 0
(n − 5) (4n + 18) = 0
Either n − 5 = 0 or 4n + 18 = 0
n = 5 or
However, n can neither be negative nor fractional.
Therefore, n = 5
an = a + (n − 1)d
a5 = 2 + (5 − 1)8
= 2 + (4) (8)
= 2 + 32 = 34
(vii) Given that, a = 8, an = 62, Sn = 210
n = 6
an = a + (n − 1)d
62 = 8 + (6 − 1)d
62 − 8 = 5d
54 = 5d
(viii) Given that, an = 4, d = 2, Sn = −14
an = a + (n − 1)d
4 = a + (n − 1)2
4 = a + 2n − 2
a + 2n = 6
a = 6 − 2n (i)
−28 = n (a + 4)
−28 = n (6 − 2n + 4) {From equation (i)}
−28 = n (− 2n + 10)
−28 = − 2n2 + 10n
2n2 − 10n − 28 = 0
n2 − 5n −14 = 0
n2 − 7n + 2n − 14 = 0
n (n − 7) + 2(n − 7) = 0
(n − 7) (n + 2) = 0
Either n − 7 = 0 or n + 2 = 0
n = 7 or n = −2
However, n can neither be negative nor fractional.
Therefore, n = 7
From equation (i), we obtain
a = 6 − 2n
a = 6 − 2(7)
= 6 − 14
= −8
(ix)Given that, a = 3, n = 8, S = 192
192 = 4 [6 + 7d]
48 = 6 + 7d
42 = 7d
d = 6
(x)Given that, l = 28, S = 144 and there are total of 9 terms.
(16) × (2) = a + 28
32 = a + 28
a = 4
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q4
How many terms of the AP. 9, 17, 25 … must be taken to give a sum of 636?
Let there be n terms of this A.P.
For this A.P., a = 9
d = a2 − a1 = 17 − 9 = 8
636 = n [9 + 4n − 4]
636 = n (4n + 5)
4n2 + 5n − 636 = 0
4n2 + 53n − 48n − 636 = 0
n (4n + 53) − 12 (4n + 53) = 0
(4n + 53) (n − 12) = 0
Either 4n + 53 = 0 or n − 12 = 0
or n = 12
n cannot be . As the number of terms can neither be negative nor fractional, therefore, n = 12 only.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q5
The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.
Given that,
a = 5
l = 45
Sn = 400
n = 16
l = a + (n − 1) d
45 = 5 + (16 − 1) d
40 = 15d
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q6
The first and the last term of an AP are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum?
Given that,
a = 17
l = 350
d = 9
Let there be n terms in the A.P.
l = a + (n − 1) d
350 = 17 + (n − 1)9
333 = (n − 1)9
(n − 1) = 37
n = 38
Thus, this A.P. contains 38 terms and the sum of the terms of this A.P. is 6973.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q7
Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.
d = 7
a22 = 149
S22 = ?
an = a + (n − 1)d
a22 = a + (22 − 1)d
149 = a + 21 × 7
149 = a + 147
a = 2
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q8
Find the sum of first 51 terms of an AP whose second and third terms are 14 and 18 respectively.
Given that,
a2 = 14
a3 = 18
d = a3 − a2 = 18 − 14 = 4
a2 = a + d
14 = a + 4
a = 10
= 5610
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q9
If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of first n terms.
Given that,
S7 = 49
S17 = 289
7 = (a + 3d)
a + 3d = 7 (i)
Similarly,
17 = (a + 8d)
a + 8d = 17 (ii)
Subtracting equation (i) from equation (ii),
5d = 10
d = 2
From equation (i),
a + 3(2) = 7
a + 6 = 7
a = 1
= n2
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q10
Show that a1, a2 … , an , … form an AP where an is defined as below
(i) an = 3 + 4n
(ii) an = 9 − 5n
Also find the sum of the first 15 terms in each case.
(i) an = 3 + 4n
a1 = 3 + 4(1) = 7
a2 = 3 + 4(2) = 3 + 8 = 11
a3 = 3 + 4(3) = 3 + 12 = 15
a4 = 3 + 4(4) = 3 + 16 = 19
It can be observed that
a2 − a1 = 11 − 7 = 4
a3 − a2 = 15 − 11 = 4
a4 − a3 = 19 − 15 = 4
i.e., ak + 1 − ak is same every time. Therefore, this is an AP with common difference as 4 and first term as 7.
= 15 × 35
= 525
(ii) an = 9 − 5n
a1 = 9 − 5 × 1 = 9 − 5 = 4
a2 = 9 − 5 × 2 = 9 − 10 = −1
a3 = 9 − 5 × 3 = 9 − 15 = −6
a4 = 9 − 5 × 4 = 9 − 20 = −11
It can be observed that
a2 − a1 = − 1 − 4 = −5
a3 − a2 = − 6 − (−1) = −5
a4 − a3 = − 11 − (−6) = −5
i.e., ak + 1 − ak is same every time. Therefore, this is an A.P. with common difference as −5 and first term as 4.
= −465
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q11
If the sum of the first n terms of an AP is 4n − n2, what is the first term (that is S1)? What is the sum of first two terms? What is the second term? Similarly find the 3rd, the10th and the nth terms.
Given that,
Sn = 4n − n2
First term, a = S1 = 4(1) − (1)2 = 4 − 1 = 3
Sum of first two terms = S2
= 4(2) − (2)2 = 8 − 4 = 4
Second term, a2 = S2 − S1 = 4 − 3 = 1
d = a2 − a = 1 − 3 = −2
an = a + (n − 1)d
= 3 + (n − 1) (−2)
= 3 − 2n + 2
= 5 − 2n
Therefore, a3 = 5 − 2(3) = 5 − 6 = −1
a10 = 5 − 2(10) = 5 − 20 = −15
Hence, the sum of first two terms is 4. The second term is 1. 3rd, 10th, and nth terms are −1, −15, and 5 − 2n respectively.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q118
A spiral is made up of successive semicircles, with centres alternately at A and B, starting with centre at A of radii 0.5, 1.0 cm, 1.5 cm, 2.0 cm, ……… as shown in figure. What is the total length of such a spiral made up of thirteen consecutive semicircles?
Semi-perimeter of circle = πr
I1 = π(0.5)
I2 = π(1) = π cm
I3 = π(1.5) =
Therefore, I1, I2, I3 ,i.e. the lengths of the semi-circles are in an A.P.,
S13 =?
We know that the sum of n terms of an a A.P. is given by
= 143
Therefore, the length of such spiral of thirteen consecutive semi-circles will be 143 cm.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q12
Find the sum of first 40 positive integers divisible by 6.
The positive integers that are divisible by 6 are
6, 12, 18, 24 …
It can be observed that these are making an A.P. whose first term is 6 and common difference is 6.
a = 6
d = 6
S40 =?
= 20[12 + (39) (6)]
= 20(12 + 234)
= 20 × 246
= 4920
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q13
Find the sum of first 15 multiples of 8.
The multiples of 8 are
8, 16, 24, 32…
These are in an A.P., having first term as 8 and common difference as 8.
Therefore, a = 8
d = 8
S15 =?
= 960
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q14
Find the sum of the odd numbers between 0 and 50.
The odd numbers between 0 and 50 are
1, 3, 5, 7, 9 … 49
Therefore, it can be observed that these odd numbers are in an A.P.
a = 1
d = 2
l = 49
l = a + (n − 1) d
49 = 1 + (n − 1)2
48 = 2(n − 1)
n − 1 = 24
n = 25
= 625
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q15
A contract on construction job specifies a penalty for delay of completion beyond a certain date as follows: Rs. 200 for the first day, Rs. 250 for the second day, Rs. 300 for the third day, etc., the penalty for each succeeding day being Rs. 50 more than for the preceding day. How much money the contractor has to pay as penalty, if he has delayed the work by 30 days.
It can be observed that these penalties are in an A.P. having first term as 200 and common difference as 50.
a = 200
d = 50
Penalty that has to be paid if he has delayed the work by 30 days = S30
= 15 [400 + 1450]
= 15 (1850)
= 27750
Therefore, the contractor has to pay Rs 27750 as penalty.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q16
A sum of Rs 700 is to be used to give seven cash prizes to students of a school for their overall academic performance. If each prize is Rs 20 less than its preceding prize, find the value of each of the prizes.
Let the cost of 1st prize be P.
Cost of 2nd prize = P − 20
And cost of 3rd prize = P − 40
It can be observed that the cost of these prizes are in an A.P. having common difference as −20 and first term as P.
a = P
d = −20
Given that, S7 = 700
a + 3(−20) = 100
a − 60 = 100
a = 160
Therefore, the value of each of the prizes was Rs 160, Rs 140, Rs 120, Rs 100, Rs 80, Rs 60, and Rs 40.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P113 - Q17
In a school, students thought of planting trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be the same as the class, in which they are studying, e.g., a section of class I will plant 1 tree, a section of class II will plant 2 trees and so on till class XII. There are three sections of each class. How many trees will be planted by the students?
It can be observed that the number of trees planted by the students is in an AP.
1, 2, 3, 4, 5………………..12
First term, a = 1
Common difference, d = 2 − 1 = 1
= 6 (2 + 11)
= 6 (13)
= 78
Therefore, number of trees planted by 1 section of the classes = 78
Number of trees planted by 3 sections of the classes = 3 × 78 = 234
Therefore, 234 trees will be planted by the students.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P114 - Q19
200 logs are stacked in the following manner: 20 logs in the bottom row, 19 in the next row, 18 in the row next to it and so on. In how many rows are the 200 logs placed and how many logs are in the top row?
It can be observed that the numbers of logs in rows are in an A.P.
20, 19, 18…
For this A.P.,
a = 20
d = a2 − a1 = 19 − 20 = −1
Let a total of 200 logs be placed in n rows.
Sn = 200
400 = n (40 − n + 1)
400 = n (41 − n)
400 = 41n − n2
n2 − 41n + 400 = 0
n2 − 16n − 25n + 400 = 0
n (n − 16) −25 (n − 16) = 0
(n − 16) (n − 25) = 0
Either (n − 16) = 0 or n − 25 = 0
n = 16 or n = 25
an = a + (n − 1)d
a16 = 20 + (16 − 1) (−1)
a16 = 20 − 15
a16 = 5
Similarly,
a25 = 20 + (25 − 1) (−1)
a25 = 20 − 24
= −4
Clearly, the number of logs in 16th row is 5. However, the number of logs in 25th row is negative, which is not possible.
Therefore, 200 logs can be placed in 16 rows and the number of logs in the 16th row is 5.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P114 - Q20
In a potato race, a bucket is placed at the starting point, which is 5 m from the first potato and other potatoes are placed 3 m apart in a straight line. There are ten potatoes in the line.
The distances of potatoes are as follows.
5, 8, 11, 14…
It can be observed that these distances are in A.P.
a = 5
d = 8 − 5 = 3
= 5[10 + 9 × 3]
= 5(10 + 27) = 5(37)
= 185
As every time she has to run back to the bucket, therefore, the total distance that the competitor has to run will be two times of it.
Therefore, total distance that the competitor will run = 2 × 185
= 370 m
Alternatively,
The distances of potatoes from the bucket are 5, 8, 11, 14…
Distance run by the competitor for collecting these potatoes are two times of the distance at which the potatoes have been kept. Therefore, distances to be run are
10, 16, 22, 28, 34,……….
a = 10
d = 16 − 10 = 6
S10 =?
= 5[20 + 54]
= 5 (74)
= 370
Therefore, the competitor will run a total distance of 370 m.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P115 - Q1
Which term of the A.P. 121, 117, 113 … is its first negative term?
[Hint: Find n for an < 0]
Given A.P. is 121, 117, 113 …
a = 121
d = 117 − 121 = −4
an = a + (n − 1) d
= 121 + (n − 1) (−4)
= 121 − 4n + 4
= 125 − 4n
We have to find the first negative term of this A.P.
Therefore, 32nd term will be the first negative term of this A.P.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P115 - Q2
The sum of the third and the seventh terms of an A.P is 6 and their product is 8. Find the sum of first sixteen terms of the A.P.
We know that,
an = a + (n − 1) d
a3 = a + (3 − 1) d
a3 = a + 2d
Similarly, a7 = a + 6d
Given that, a3 + a7 = 6
(a + 2d) + (a + 6d) = 6
2a + 8d = 6
a + 4d = 3
a = 3 − 4d (i)
Also, it is given that (a3) × (a7) = 8
(a + 2d) × (a + 6d) = 8
From equation (i),
From equation (i),
a=3-4d
=3-2=1
=20
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P115 - Q3
A ladder has rungs 25 cm apart. (See figure). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and bottom rungs are m apart, what is the length of the wood required for the rungs?
[Hint: number of rungs]
It is given that the rungs are 25 cm apart and the top and bottom rungs are m apart.
∴ Total number of rungs
Now, as the lengths of the rungs decrease uniformly, they will be in an A.P.
The length of the wood required for the rungs equals the sum of all the terms of this A.P.
First term, a = 45
Last term, l = 25
n = 11
Therefore, the length of the wood required for the rungs is 385 cm.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P115 - Q4
The houses of a row are number consecutively from 1 to 49. Show that there is a value of x such that the sum of numbers of the houses preceding the house numbered x is equal to the sum of the number of houses following it.
Find this value of x.
[Hint Sx − 1 = S49 − Sx]
The number of houses was
1, 2, 3 … 49
It can be observed that the number of houses are in an A.P. having a as 1 and d also as 1.
Let us assume that the number of xth house was like this.
We know that,
Sum of n terms in an A.P.
Sum of number of houses preceding xth house = Sx − 1
Sum of number of houses following xth house = S49 − Sx
It is given that these sums are equal to each other.
However, the house numbers are positive integers.
The value of x will be 35 only.
Therefore, house number 35 is such that the sum of the numbers of houses preceding the house numbered 35 is equal to the sum of the numbers of the houses following it.
CBSE 10th Maths Chap 5 - Arithmetic Progressions - P115 - Q5
A small terrace at a football ground comprises of 15 steps each of which is 50 m long and built of solid concrete.
Each step has a rise of m and a tread of
m (See figure) calculate the total volume of concrete required to build the terrace.
From the figure, it can be observed that
1st step is m wide,
2nd step is 1 m wide,
3rd step is m wide.
Therefore, the width of each step is increasing by m each time whereas their height
m and length 50 m remains the same.
Therefore, the widths of these steps are
Volume of concrete in 1st step
Volume of concrete in 2nd step
Volume of concrete in 3rd step
It can be observed that the volumes of concrete in these steps are in an A.P.
Volume of concrete required to build the terrace is 750 m3.
CBSE 10th Maths Chap 6 - Triangles
CBSE 10th Maths Chap 7 - Coordinate Geometry
CBSE 10th Maths Chap 8 - Introduction to Trigonometry
CBSE 10th Maths Chap 9 - Some Applications of Trigonometry
CBSE 10th Maths Chap 10 - Circles
CBSE 10th Maths Chap 11 - Constructions
CBSE 10th Maths Chap 12 - Areas Related to Circles
CBSE 10th Maths Chap 13 - Surface Areas and Volumes
CBSE 10th Maths Chap 14 - Statistics
CBSE 10th Maths Chap 15 - Probability
CBSE Class X Previous Question Papers 2007
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CBSE EXAM Question Papers for Board Examinations 2011 (CLASS X)
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Chap 14 - Sources of Energy - P255 - Q8
What are the qualities of an ideal source of energy?
An ideal source of energy must be:
I. Economical
II. Easily accessible
III. Smoke/pollution free
Chap 7 - Control and Coordination - P125 - Q4
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Chap 8 - How do Organisms Reproduce? - P141 - Q4
What are the advantages of sexual reproduction over asexual reproduction?