QUESTION_BANK_CLASS_X

ATAL SAHODAYA CLASS – X MCQ QUESTION BANK TERM - 1

SCIENCE

Chapter – CHEMCIAL REACTIONS AND EQUATIONS 1. During burning of magnesium, we should wear sun glasses to protect our eyes from white dazzling light as it: (a) damage the retina (b) leads to loss of our vision (c) both (a) & (b) (d) none of these Answer: (c) both (a) & (b) 2. Fermentation of grapes is considered as a chemical reaction as it is a (a) chemical change (b) sugar in grapes converts into alcohol (c) Irreversible change (d) all the above Answer: (d) all the above 3. During photosynthesis, energy is absorbed by chlorophyll, therefore it is: (a) exothermic reaction (b) endothermic reaction (c) neither exothermic nor endothermic reaction (d) the process takes place in plants only Answer: (b) endothermic reaction 4. Which of the following sign shows that a product is obtained as a precipitate? (a) (b) (c) (d) Answer: (d) 5. Given below equation represents: H2 (g) + O2 (g)  H2O (l) (a) skeleton chemical reaction (b) skeletal chemical equation (c) chemical equation (d) none of the above Answer: (b) skeletal chemical equation 6. xFe + yH2O  Fe3O4 + zH2 What are x, y, z in balanced equation respectively? (a) 3, 4, 4 (b) 3, 4, 2 (c) 2, 4, 3 Answer: (a) 3, 4, 4 7. Which of the following observations is / are not correct about the given equation: Pb(NO3)2 (aq) + 2 KI (aq)  PbI2 (s) + 2KNO3 (aq) (a) PbI2 is yellow precipitate insoluble in water (b) It is precipitation reaction (c) It is single displacement reaction (d) It is very fast reaction Answer: (c) It is single displacement reaction 8. A green coloured solid compound ‗X‘, gets oxidized to reddish brown solid in presence of air. ‗X‘ on heating gives brown coloured solid ‗Y‘ and two pungent smelling gases ‗A‘ and ‗B‘. ‗A‘ turns acidified potassium dichromate solution green. Name ‗X‘, ‗Y‘, ‗A‘ , ‗B‘ and type of Reaction. (a) CuSO4, CuO, SO2, SO3, decomposition (b) FeSO4, Fe, SO2, SO3, decomposition (c) FeSO4, Fe2O3, SO2, SO3, decomposition (d) FeSO4, Fe2O3, SO3, SO2, decomposition Answer: (c) FeSO4, Fe2O3, SO2, SO3, decomposition 9. Rusting of iron and respiration: (a) both are exothermic processes (b) both are endothermic processed (c) rusting is exothermic, respiration is endothermic

(d) rusting is endothermic, respiration is exothermic Answer: (a) both are exothermic processes 10. On immersing gold pins in CuSO4 solution for few minutes, you will observe (a) displacement reaction (b) the colour of solution fades away (c) the surface of gold pins acquire a black coating (d) No change Answer: (d) No change 11. Which of the following statements about the given reaction are correct? 3Fe(s) + 4H₂O(g) → Fe₃O₄ (s) + 4H₂ (g) (a) Iron metal is getting oxidized. (b) Water is getting reduced. (c) Water is acting as reducing agent. (d)Water is acting as oxidizing agent. A) (A), (B) & (C) B) (C) & (D) C) (A), (B) & (D) D) (B) & (D) Answer: (c) (A), (B) & (D) 12. Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved? (a) Displacement reaction (b) Precipitation reaction (c) Combination reaction (d) Double displacement reaction A) Only (A) B) Only (B) C) Only (D) D) (B) & (D) Answer: (d) (B) & (D) 13. Which of the following statement(s) is (are) true for the given situation? Exposure of silver chloride to sunlight for a long duration turns grey due to (i) formation of silver by decomposition of silver chloride (ii) sublimation of silver chloride (iii) decomposition of chlorine gas from silver chloride (iv) oxidation of silver chloride (a) (i) only (b) (ii), (i) and (iii) (c) (ii) and (iii) (d) (iv) only Answer: (a) (i) only 14. The displacement reaction between iron (III) oxide and a metal X is used for welding the rail tracks. Here X is: (a) Copper granules (b) Magnesium ribbon (c) Sodium pellets (d) Aluminum dust Answer: (d) Aluminum dust

15. The chemical reaction between Hydrogen sulphide and iodine to give Hydrogen iodide and sulphur is given below: The oxidizing and reducing agents involved in this redox reaction are: (a) Iodine and sulphur respectively (b) Iodine and hydrogen sulphide respectively (c) Sulphur and iodine respectively (d) Hydrogen sulphide and sulphur Answer: (b) Iodine and hydrogen sulphide respectively 16. Which of the following can be used for storage of fresh sample of an oil for a long time? (a) CO2 and O2 (b) N2 and Cl2 (c) CO2 and He (d) He and N2 Answer: (d) He and N2 17. The Classical example of redox reaction is Combustion of fossil fuel. During combustion of fossil fuels, the carbon compound in the fossil fuel reacts with oxygen in the presence of a heat source to form carbon dioxide (CO2) and water. Energy is also needed for the fossil fuel to react with oxygen, so the energy used in portion of combustion is an endothermic reaction. Combustion of fossil fuel (1) Which conditions are fulfilled in case of combustion? (a) Oxygen is reduced (b) Burning compound undergoes oxidation (c) Oxygen is reducing agent (d) Both (a) and (b) Answer: (d) Both (a) and (b) (2) What happens when a substance gains oxygen during reaction? The substance gets – (a) Oxidised (b) Reduced (c) Both oxidized and reduced (d) None of the above Answer: (a) Oxidised (3) What happens when a substance loses oxygen during reaction? It is said to be (a) Oxidised (b) Reduced (c) Both (d) None of the above Answer: (b) Reduced (4) Example of redox reactions can be observed in following processes – (a) Corrosion

(b) Photosynthesis (c) Respiration (d) All of above Answer: (d) All of above (5) In the process of photosynthesis CO2 is reduced. (a) True (b) False Answer: (a) True Q. 18. Above image shows an experiment where copper sulphate crystals are heated. When we heat the crystals, they turn white. If you moisten the crystals again with water you will find that colour of crystals reappears . (1) How many water molecules are present in one formula unit of copper sulphate (a)5 (b)2 (c)6 (d)7 Answer: (a) 5 (2) If the crystal is moistened with water which colour of crystals appear---- (a) Green (b) Red (c) Blue (d) Yellow Answer: (c) Blue (3) The water of crystallization is the variable number of water molecules present in a salt – (a) True (b) False Answer: (b) False (4) The salt which does not possess water of crystallization is (a) Bleaching powder (b) Gypsum (c) Washing Soda (d) none of the above Answer: (a) Bleaching powder (5) The chemical formula for hydrated copper sulphate is – (a) CuSo4.2H2O (b) CuSo4.6H2O (c) CuSO4.4H2O (d) CuSO4.5H2O Answer (d) CuSO4.5H2O

19. A substance X, which is an oxide of an element, is used intensively in the cement industry, This element is present in bones also. On treatment with water, it forms a solution which turns red litmus blue. Substance ‘X’ (1) The substance X is an oxide of: (a) copper (b) carbon (c) calcium (d) none of the above Answer: (c) calcium (2) What is the common name of substance ‗X‘ (a) Slaking of lime (b) quick lime (c) both (a) and (b) (d) none of the above Answer: (b) quick lime (3) Slaking of lime results in the formation of (a) lime (b) quick lime (c) milk of lime (d) none of these Answer: (c) milk of lime (4) Which of the following is a correct observation when water is added to substance ‗X‘ (a) vigorous bubbling and a hissing sound (b) slow bubbling with no sound (c) vigorous bubbling with evolution of heat and a hissing sound (d) only hissing sound Answer: (c) vigorous bubbling with evolution of heat and a hissing sound (5) Reaction of substance X with water is (a) Decomposition reaction (b) Combination reaction (c) Displacement reaction (d) Double displacement reaction Answer: (b) Combination reaction 20. Decomposition of vegetable matter into compost is an example of exothermic reaction. Compost provides a stable organic matter that improves the physical, chemical and biological properties of soil, thereby enhancing soil quality and crop production. This compost can be used as fertilizers supplement by farmers in their field.

1. Which of the following is/ (are) exothermic process(es)? (a) burning of natural gas (b) dilution of an acid (c) both (a) and (b) (d) none of these Answer: (c) both (a) and (b) 2. Which among the following changes are endothermic in nature (a) decomposition of ferrous sulphate (b) dissolution of ammonium chloride in water (c) both (a) and (b) (d) dilution of hydrochloric acid Answer: (c) both (a) and (b) 3. How many types of decomposition reaction are there: (a) 1 (b) 2 (c) 3 (d) 4 Answer: (c) 3 4. During decomposition, energy is absorbed in the form of heat, light or electricity for breaking down the reactants which is known as: (a) exothermic reaction (b) endothermic reaction (c) reduction reaction (d) oxidation Answer: (b) endothermic reaction 5. All decomposition reaction are endothermic but decomposition of vegetable matter into compost is exothermic because (a) It is an oxidation reaction (b) decomposition done by microbes (c) releases heat energy (d) all the above Answer: (d) all the above Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below: (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A. (c) A is true but R is false. (d) A is false but R is true.

(e) Both A and R are false. 21. Assertion (A): Lead nitrate on thermal decomposition gives lead oxide, brown colored nitrogen dioxide and oxygen gas. Reason (R): Lead nitrate reacts with potassium iodide to form yellow ppt. of lead iodide and the reaction is double displacement as well as precipitation reaction. Answer: (b) )Both A and R are true but R is not the correct explanation of A 22. Assertion(A): The Chemical reaction during which hydrogen is lost is called reduction. Reason(R): Reducing agent removes hydrogen Answer: (e) Both A and R are false 23. Assertion(A): Method used for balancing chemical equation is called hit and trial method. Reason(R): As we make trials to balance the equation by using the smallest whole number coefficient. Answer: (a) Both A and R are true and R is the correct explanation of A. 24. Assertion(A): After white washing the walls, a shiny white finish on walls is obtained after two or three days. Reason(R): Calcium oxide reacts with carbon dioxide to form calcium hydrogen carbonate which gives shiny white finish. Answer: (c) A is true but R is false. 25. Assertion(A): During chemical reaction atoms of one element do not change into those of another element nor disappear from the mixture. Reason(R): As chemical reaction involves the breaking and making of bonds between atoms to produce new substance. Answer: (a) Both A and R are true and R is the correct explanation of A.

Chapter-2, ACID BASE AND SALT 1. Which one of the following salts does not contain water of crystallisation? a) Soda Blue vitriol b) Baking soda c) Washing d) Gypsum Answer: (b) Baking soda 2. Tomato is a natural source of which acid? a) Acetic acid b) Citric acid c) Tartaric acid d) Oxalic acid Answer: (d) Oxalic acid 3. Lime water reacts with chlorine to give a) bleaching powder b) baking powder c) baking soda d) washing soda Answer: (a) bleaching powder 4. Antacid contain a) Weak acid b) Weak base c) Strong acid d) Strong base Answer: (b) weak base 5. What is the natural colour of lichen‘s juice? a) Blue b) Red c) Purple d) Orange Answer: (c) purple 6. Which one of the following salts does not con-tain water of crystallisation? a) Blue vitriol b) Baking soda c) Washing soda d) Gypsum Answer: (b) Baking soda 7. Brine is an a) aqueous solution of sodium hydroxide b) aqueous solution of sodium carbonate c) aqueous solution of sodium chloride d) aqueous solution of sodium bicarbonate Answer: (c) aqueous solution of sodium chloride 8. At what temperature is gypsum heated to form Plaster of Paris?

a) 90°C b) 100°C c) 110°C d) 120°C Answer: (b) 100°C 9. The pH of gastric juice released during digestion is a) Less than seven b) More than seven c) Equal to seven d) Equal to zero Answer: (a) less than seven 10. Which of the following is acidic in nature? a) Apple juice b) Soap solution c) Slaked lime d) Lime Answer: (a) apple juice 11. Nettle sting is a natural source of which acid? a) Methanoic acid b) Lactic acid c) Citric acid d) Tartaric acid Answer: (a) methanoic acid 12. Tooth enamel is made up of: a) Potassium b) Calcium carbonate c) Calcium phosphate d) Calcium oxide Answer: (c) calcium phosphate 13. The pH of acidic rain is a) Below 7 b) Below 6 c) Below 5.6 d) Above 7 Answer: below 5.6 14. 1.Which of the following statements is correct about an aqueous solution of an acid and of a base? (i) Higher the pH, stronger the acid (ii) Higher the pH, weaker the acid (iii) Lower the pH, stronger the base (iv) Lower the pH, weaker the base (a) (i) and (iii) (b) (ii) and (iii (c) (i) and (iv) (d) (ii) and (iv)

Answer: d (ii) and (iv) 15. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change? (a) Baking powder (b) Lime (c) Ammonium hydroxide solution (d) Hydrochloric acid Answer: d Hydrochloric acid 16. Which one of the following salts does not contain water of crystallisation? (a) Blue vitriol (b) Baking soda (c) Washing soda (d) Gypsum Answer : b in manufacturing of soap 4 . Sodium hydroxide is used (a) as an antacid (b) as a cleansing agent (c) in manufacturing of soap (d) in alkaline batteries Answer: c in manufacturing of soap 5. What is formed when zinc reacts with sodium hydroxide? (a) Zinc hydroxide and sodium (b) Sodium zincate and hydrogen gas (c) Sodium zinc-oxide and hydrogen gas (d) Sodium zincate and water Answer: b Sodium zincate and hydrogen gas 6. An ant‘s sting can be treated with …………which will neutralise the effect of the chemical injected by the ant‘s sting into our skin. (a). Methanoic acid (b). formic acid (c). Baking soda (d). Caustic soda Answer: c Baking soda 7. Copper sulphate crystals when heated strongly, lose their water of crystallization to give anhydrous copper sulphate accompanied by a change in color from: (a). Blue to green (b). Blue to white (c). Blue to sky blue (d). Blue to grey Answer: b Blue to white

8. Zinc granules on treating with an acid X, form the zinc sulphate (ZnSO4) salt along with the evolution of a gas Y which burns with a pop sound when brought near to a burning candle. Identify the acid X and gas evolved Y (a). X- Sulphuric acid and Y- Oxygen gas (b). X- Hydrochloric acid and Y- Oxygen gas (c). X- Sulphuric acid and Y- Hydrogen gas (d). X- Hydrochloric acid and Y- Hydrogen gas Answer : c X- Sulphuric acid and Y- Hydrogen gas 9. Which of the following acid is also known as vinegar? (a) Dilute hydrochloric acid (b) Dilute sulphuric acid (c) Dilute acetic acid (d) Dilute tartaric acid Answer : c) Dilute acetic acid 10.What happens when excess of carbon dioxide gas is passed through lime water? (a) Lime water first turns milky and then colorless (b) Lime water turns bluish me water turns milky (d) Lime water turns blackish Answer : (a) Lime water first turns milky and then colorless 11. The nature of calcium phosphate present in tooth enamel is (a)Basic (b)Acidic (c ) Neutral (d) Amphoteric Answer: (a) Basic 12. Acid Reacts with metals and released…………gas. (a) Carbon di oxide (b) Water (c) Hydrogen (d) None Answer: (c) Hydrogen 13 .During neutralization reaction acids react with ……..to form ……..and water. (a) Metals ,Gas (b) Bases, Salt (c) Non-Metal , Salt (d)Acids ,Salts Answer: (bs) Bases Salt 14. The range of pH of human body is (a) 7.0-8.0 (b) 7.0- 7.8 (c) 7.2-8.2 (d) None Answer: (b) 7.0-7.8 15. Gypsum is heated at……..temperature to form plaster of paris.

(a) 110degree Celsius (b) 120degree Celsius (c) 100degree Celsius (d) 101degree Celsius Answer: (c) 100degree Celsius 16. When a bee stings ,a paste of calamine is applied because (a) Bee sting consist of base. (b) To neutralized the effect of formic acid injected via bee sting (c) Both (A) and (B) (d) None Answer: (b) To neutralized the effect of Formic acid injected via bee sting. 17. Indigestion can be treated by using (a) Antibiotics (b) Antiseptic (c) Antacid (d) All of these Answer: Antacid 18. In phenolphthalein solution bases turns into (a) Pink (b) Yellow (c) Orange (d) Colourless Answer: (a) Pink 19. An indicator is one kind of the following compound (a) Reducing agent. (b) Salt (c) Base (d) Weak base or acid only Answer: (d) Weak base or acid only. 20. A metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives carbonate back..Identify X and Y. (a) X is sodium carbonate and Y is Sodium hydroxide (b) X is Calcium carbonate and Y is calcium hydroxide (c ) X is Potassium carbonate and Y is Potassium hydroxide. (d) None of above Answer: (b) X is calcium carbonate and Y is Calcium hydroxide. 21. A sulphate salt of group 2 element of the periodic table is white ,soft substance which can be moulded into different shapes by making its dough.Identify the salt . (a) CaSO4.1/2 H2O (b) CaSO4.2H2O (c) 2CaSO4. ½ H2O (d)CaSO4 Answer:- (a) CasO4.1/2 H2O 22. Identify the compound X and A on the basis of the reaction given below. X +Zn A + H2 (a)X is Sodium hydroxide and A is sodium zincate (b)X is Sodium hydroxide and A is sodium chloride

©X is sodium hyroxide and A is sodium ethanoate (d)Both a and c Answer:- (a) X is Sodium hydroxide and A is sodium zincate 23. Name the acid present in Ant sting and its chemical formula. (a) Methanoic acid and HCOOH (b) Formic acid and HCOOH (c) Acetic acid and CH3COOH (d) Both a and b Answer:- (d) ) Both a and b 24. The reagent used to distinguish iron(II) chloride and iron (ii) chloride (a)distilled water (b) NaOH (c) dil HCl (d) warm water Answer:- (b) ) NaOH 25.Which among the following is not a base? (a) NaOH (b) KOH ( c) NH4OH (d)C2H5 OH Answer:-( d) C2H5 OH

ASSERTION REASON BASED QUESTION Directions: In the following questions, a statement of assertion is followed by a statement of reason. Mark the correct choice as: (a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion. (b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion. (c) If Assertion is true but Reason is false. (d) If Assertion is false and Reason are true. 1. Assertion (A): The aqueous solutions of glucose and alcohol do not show acidic character. Reason (R): Aqueous solutions of glucose and alcohol do not give H+ ions. Answer: (a) both Assertion and Reason are true and Reason is the correct explanation of Assertion. 2. Assertion (A): Pure water is neither acidic nor basic. Reason (R): The pH of a solution is universally proportional to the concentration of hydrogen in it. Answer: (b) both Assertion and Reason are true but Reason is not the correct explanation of Assertion. 3. Assertion (A): On adding H2SO4 to water the resulting aqueous solution get corrosive. Reason (R): Hydronium ions are responsible for corrosive action. Answer (a) both Assertion and Reason are true and Reason is the correct explanation of Assertion. 4. Assertion (A) : During electrolysis of concentrated aqueous solution of sodium chloride, hydrogen is produced at anode and chlorine gas is produced at cathode. Reason (R) : Ions get attracted to oppositely charged electrodes. Answer : d A is false but R is true. 5. Assertion (A) : The aqueous solutions of glucose and alcohol do not show acidic character. Reason (R) : Aqueous solutions of glucose and alcohol do not give H+ ions. Answer : a Both A and R are true and R is the correct explanation of A 6. Assertion (A) : Dry HCl gas does not change the colour of dry blue litmus paper. Reason (R) : HCl gas dissolves in the water present in wet litmus paper to form H+ ions. Answer : b Both A and R are true but R is not the correct explanation of A. 7. Assertion (A) : washing soda is sodium carbonate hexahydrate. Reason (R) : chlorine is used for making bleaching powder. Answer : d A is false but R is true. 8. . Assertion (A) : Gypsum contain 2 water of crystallization. Reason (R) : Gypsum is heated at 373k to give P.O.P Answer : b Both A and R are true but R is not the correct explanation of A

9. Assertion: Pure water is neither acidic nor basic. Reason: The ph of a solution is inversely proportional to the concentration of H ions Answer : (b) Both Assertion and reason is true but Reason is not a correct explanation of Assertion. 10.. Assertion: pH=7 means pure water. Reason: pH of acetic acid is greater than 7. Answer: (c) Assertion is true but reason is false. 11. Assertion: The reason of tooth decay is the value of pH lower than 5.5 in mouth. Reason : Enamel starts to corrod less than 5.5pH. Answer : (a) Both Assertion and reason are true and reason is the correct explanation of assertion. 12. Assertion: Al2O3, is an amphoteric oxide. Reason: Al2O3 reacts with acid as well as base to form salt and water. Answer: (a) Both A and R are true but R is the correct explanation of A 13. Assertion:-When zinc is added to dilute hydrochloric acid ,hydrogen is given off. Reason:- Hydrogen chloride molecules contain hydrochloric acid and hydrogen atoms. Answer:- (b) Both A and R are true but R is not the correct explanation of A 14. Assertion:-In water hydrochloric acid behaves as a weak monobasic acid. Reason:- In water ,hydrochloric acid acts as a proton donor. Answer:-(d) A is false but R is true

CASE STUDY BASED QUESTIONS A child was suffering from stomach pain for a number of days. He consulted a doctor who advised him to take two antacid tablets after each meal for about a week and avoid spicy food. Child followed the advise strictly and was cured. 1. What was the problem faced by the child? a) Anaemia b) Acidity c) Anxiety d) Diarrhoea Answer: (b) acidity 2. NaHCO3 + HCl NaCl + H2O +CO2 is the correct chemical reaction happening inside stomach when child takes antacid. (a) Yes (b) No (c) May be Answer: (a) yes 3. Antacid reduces the excess ..................... in the stomach. a) Water b) Base c) Acid d) None of these Answer: (c) acid 4. Prolonged severe acidity may cause a) Hypertension b) Ulcer c) Anxiety d) Hepatitis Answer: (b) ulcer pH is quite useful to us in a number of ways in daily life. Some of its applications are: Control of pH of the soil: Plants need a specific pH range for proper growth. The soil may be acidic, basic or neutral depending upon the relative concentration of H+ and OH-. The pH of any soil can be determined by using pH paper. If the soil is too acidic, it can be corrected by adding lime to it. If the soil is too basic, it can be corrected by adding organic manure which contains acidic materials Regaining shine of a tarnished copper vessel by use of acids: A copper vessel gets tarnished due to formation of an oxide layer on its surface. On rubbing lemon on the vessel, the surface is cleaned and the vessel begins to shine again. This is due to the fact that copper oxide is basic in nature, which reacts with the acid (citric acid) present in lemon to form a salt (copper citrate) which is washed away with water. As a result, the layer of copper oxide is removed from the surface of the vessel and the shining surface is exposed. Q5-9 BASED ON ABOVE PARAGRAPH (5) When black copper oxide placed in a beaker is treated with dilute HCl, its colour changes to……… a) White

b) Red c) Blue-green d) No change ANSWER : c) blue-green (6) P is an aqueous solution of acid and Q is an aqueous solution of base. When these two are diluted separately, then a) pH of A increases and pH of B decreases b) pH of A inceases and pH of B decreases till pH in each case is 7 c) pH of A and B increase d) pH of A and B decrease ANSWER : a) pH of A increases and pH of B decreases (7) Which of the following acids is present in bee sting? a) Methanoic acid b) Citric acid c) Hydrochloric acid d) Tartaric acid ANSWER : a) Methanoic acid (8) Sting of ant can be cured by rubbing the affected area with soap because (a) it contains oxalic acid which neutralises the effect of formic acid (b) it contains aluminium hydroxide which neutralises the effect of formic acid (c) it contains sodium hydroxide which neutralises the effect of formic acid (d) none of these ANSWER : (c) it contains sodium hydroxide which neutralises the effect of formic acid (9) The pH of soil X is 7.5 while that of soil Y is 4.5. Which of the two soils, should be treated with powdered chalk to adjust its pH? (a) X only (b) Y only (c) Both X and Y (d) None of these ANSWER : b) Y only Read the following and answer any four questions: Salt of a strong acid and strong base is neutral with a pH value of 7. NaCl common salt is formed by a combination of hydrochloride and sodium hydroxide solution. This is the salt that is used in food. Some salt is called rock salts bed of rack salt were formed when seas of bygone ages dried up. The common salt thus obtained is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, bleaching powder. 10. Which of the following salt has water of crystallization? (A) Washing soda (B) Baking soda (C) Gypsum (D) None

Answer: c Gypsum 11. The formula of common salt is (A) CaOH (B) KOH (C) NaCl (D) HCl Answer: (C) NaCl 12. The salt which is used to remove the hardness of water is (A) NaOH (B)Baking Soda (C) Bleaching powder (D) All of these Answer: (C) Bleaching powder 13. Butyric acid is found in (A) Bees sting (B) Rancid cake (C) Butter (D) None Answer: (B) Rancid cake 14. The chemical name of Bleaching powder is (A)Calcium Chloride (B) Calcium Chloro-Oxide (C) Calcium Oxychloride (D) Hypochloride Answer: (C) Calcium Oxychloride 15. The colour of Methyl orange in basic solution is (A)Orange (B) Pink (C) Yellow (D) Colourless Answer: (C) Yellow 16. Acid present in Tomato is (A)Lactic acid (B) Tartaric acid (C) Oxalic acid (D) Citric acid Baking soda is used in kitchens for making tasty pakora, sometimes it is added to make cooking faster.it also helps to prepare baking powder.Not only this ,it is also used in fire extinguisher. 17. Baking soda is

(a) acidic (b) basic (c) neutral (d) buffer Ans (b) basic 18. Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal the hardness of water and a gas C is evolved. The gas C when passed through lime water ,turns it milky. Identify A,B and C. (a) A is sodium hydrogen carbonate ,B is hydrous sodium carbonate and c is carbon dioxide (b)A is sodium carbonate ,B is sodium hydrogen carbonate and c is Carbon monoxide © A is baking soda ,B is washing soda and C is carbon dioxide (d) both a and c Ans;-( d) both a and c (19) What is baking powder? (a) mixture of baking soda with tartaric acid (b) mixture of washing soda with citric acid (c) mixture of sodium hydrogen carbonate with edible acid (d) option a and c both Ans (d )option a and c both (20) What is the name and chemical formula of the main product formed by heating baking soda. (a) sodium carbonate,Na 2CO3 (b) Bleaching powder ,CaOCl2 (c) sodium chloride,Na Cl (d)Plaster of paris ,CaSO4.I/2H2O Answer (a) sodium carbonate,Na 2CO3 Washing soda has been known and used since early times.It is crystalline in form .It can be prepared by reaction of sodium chloride .It has different properties. (21) Name the process by which washing soda is prepared. (a)Solvay process (b) ammonium soda process (c) Both (a) and (b) (d)none of above Answer:- (c) (22) What will be formed when sodium hydrogen carbonate is heated? (a) Sodium hydroxide (b) Sodium carbonate (c) Sodium ash (d) Both (b) and (c) Answer:- (d)

(23) What will be formed when hydrous sodium carbonate is heated above 373 K (a) Soda ash (b) Anhydrous sodium carbonate (c) Both (a) and (c) (d) None of above Answer:- ( c) 24. The pH value of a sample of hydrochloric acid is 2.pH value of this sample when diluted by adding water will be (a) Less tha 2 but more than 0 (b) More than 2 but less than 7 (c) More than 7 (d) No change in pH Answer:- (b) More than 2 but less than 7 25. Some drops of acetic acid are poured over a pH paper. The colour produced on the paper will be (a) Green (b) Blue (c) Violet (d) Orange Answser:-(b) Blue 26.Which of the following is true when HCL is passed through water. (i) It does not ionize in the solution as it is a covalent compound (ii) It ionizes in the solution (iii) It gives both hydrogen and hydroxyl ions in the solution (iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule. (a) (i) only (b) (iii) only (c) (ii) and (iv) only (d) (iii) and (iv) Answer:-(c) (ii) and (iv) only

CHAPTER-METALS AND NON-METALS 1) Generally Non-metals are not conductors of electricity. Which of the given is a good conductor of electricity? a) Diamond b) Graphite c) Sulphur d) Fullerene Answer B)- Graphite 2) The electronic configuration of three elements X, Y and Z are X-2,8; Y-2,8,7 and Z-2,8,2‘Which of the given is correct. a) X is a metal b) Y is a metal c) Zis a non-metal d) Y is a non-metal and Z is a metal Answer d) Y is a non-metal and Z is a metal 3) An aluminium strip is kept immersed in a freshly prepared ferrous sulphate solution taken in a test tube, the change observed is that a) Green solution slowly turns brown b) Lower end of the test tube becomes slightly warm c)A colourless gas with smell of burning sulphur is evolved c)Light green solution changes to blue Answer a) Green solution slowly turns brown 4) The property of metals being beaten into thin sheets is called A) Ductility B) Malleability C)Brittle D)None of these Answer B) Malleability 5) The best conductors of heat are A) Silver and Copper B) Lead and Mercury C) Iron and Tin D) Gold and Platinum Answer A) Silver and Copper

6)The metals with very low melting points which melts by the temperature of palm are A) Sodium and potassium B) Lead and magnesium C) Aluminium and zinc D) Gallium and caesium Answer D)- Gallium and caesium 7) Al2O3 + 2NaOH → …… + H2O A) Al (OH)3 B) Na2O C) NaAlO2 D) AlNaO2 Answer C)- NaAlO2 8) An element X is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following A) Mg B) Na C)P D)Ca Answer B)-Na 9) Reaction between X and Y forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z? A) Has high melting point B) Has low melting point C) Conducts electricity in molten state D) Occurs as solid Answer B)- Explanation: Reason: Z is an ionic compound. It has a high melting point. 10) Metallic oxides which react with both acid and base to produce salt and water are called A) Neutral Oxides B) Basic Oxides C) Amphoteric Oxides D) Acidic Oxides Answer C)-Amphoteric Oxides 11) When Calcium reacts with water it starts floating on top of water because A) bubbles of carbon dioxide formed stick to the surface of metal B) bubbles of hydrogen formed stick to the surface of metal

C) Calcium is lighter than water D) None of the above Answer B)- bubbles of hydrogen formed stick to the surface of metal 12) The reactivity series is a list of metals arranged in order of A) Increasing reactivity B) Decreasing reactivity C) Increasing and decreasing reactivity D) None of the above Answer B) Decreasing reactivity 13) Ionic compounds have high melting and boiling points because A) less energy is required to break the strong interionic attraction B) large amount of energy is required to break the interionic attraction C) No energy is required D) None of the above Answer B)- large amount of energy is required to break the interionic attraction

ASSRTION & REASONING Note: For question numbers 14,15 and 16, two statements are given-one labelled Assertion (A)and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), © and (d) as given below: (a)Both A and R are true, and R is the correct explanation of the assertion. (b)Both A and R are true, butR is not the correct explanation of the assertion. (c)A is true but R is False. (d)A is false but R is true. 14)Assertion (A) Hydrogen gas is not evolved when a metal reacts with nitric acid. Reason (R)Nitric acid is a strong oxidising agent. Answer a)- Both A and R are true, and R is the correct explanation of the assertion. 15)Assertion (A)Magnesium chloride is an ionic compound. Reason(R)Metals and non-metals react with mutual transfer of electrons. Answer a)- Both A and R are true, and R is the correct explanation of the assertion. 16)Assertion (A) Gold occurs in native state. Reason (R)Gold is a reactive metal. Answer)- A is true but R is False. 17) 2 ml each of concentrated HCl, HNO3 and a mixture of concentrated hydrochloric acid and Concentrated nitric acid in the ratio of 3:1were taken in test tubes labelled as A, B and C, A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal dissolved in test tube C. The metal could be: A) Al B) Au C) Pt D) Cu Answer B) Au 18) Which of the following is the correct arrangement of the given metals in ascending order of their reactivity? Zinc, Iron, Magnesium, Sodium A) Zinc > Iron > Magnesium > Sodium B) Sodium > Magnesium > Iron > Zinc C) Sodium > Zinc > Magnesium > Iron D) sodium > Magnesium > Zinc > Iron Answer D)- Sodium > Magnesium > Zinc > Iron 19) In general the number of electrons in the outermost shell of the metal is A)1

B)1 to 3 C)5 to 8 D)8 Anwer B) 1 to 3 20) Which of the given nonmetal is a liquid? A) Hydrogen B) Bromine C) Chlorine D) Mercury Answer B)- Bromine

Chapter - HUMAN EYE 1. In the following diagram, the path of a ray of light passing through a glass prism is shown: In this diagram the angle of incidence, the angle of emergence and the angle of deviation respectively are (select the correct option): (a) X, R and T (b) Y, Q and T (c) X, Q and P (d) Y, Q and P Answer (d) Y, Q and P 2 Which of the following colour is least scattered by fog, dust or smoke : A. Violet B. Blue C. Red D. Yellow Answer c) Red 3 When a ray passes through a prism ______. A. It goes undeviated B. It remain parallel to a base C. It bends towards the base D. None Answer C. It bends towards the base 4 The ratio of real depth to apparent depth is called : A. Refractive index B. Critical angle C. Lateral displacement D. None Answer (A) refractive index 5 At noon the sun appear white as a) Light is least scattered b) All the colours of the white light are scattered away c) Red colour is scattered the most d) Blue colour is scattered the most Answer a) light is least scattered

6 The image shows the dispersion of the white light in the prism. What will be the colours of the X, Y and Z? (a) X: red; Y: green; Z: violet (b) X: violet; Y: green; Z: red (c) X: green; Y: violet; Z: red (d) X: red; Y: violet; Z: green Answer: Option (b) 7. Which of the following phenomena of light are involved in the formation of a rainbow? (a) Reflection, refraction and dispersion (b) Refraction, dispersion and total internal reflection (c) Refraction, dispersion and internal reflection (d) Dispersion, scattering and total internal reflection Answer: Option (b) Read the following and answer the following questions from (8) to (12):- Atmospheric refraction is the phenomenon of bending of light on passing through earth‘s atmosphere. As we move above the surface of earth, density of air goes on decreasing. Local conditions like temperature etc. also affect the optical density of earth‘s atmosphere. On account of atmospheric refraction, stars seen appear higher than they actual are; advanced sunrise; delayed sunset, oval appearance of the sun at sunrise and sunset; stars twinkle, planets do not. 8. Due to atmospheric refraction, apparent length of the day (a) increases (b) decreases (c) remains the same (d) all of these Answer: (a) increases (by 4 minutes.) 9. Apparent position of the star appears raised due to (a) atmospheric refraction (b) scattering of light (c) both (a) and (b) (d) none of these Answer: (a) atmospheric refraction.

10. The sun appears oval shaped or flattened due to (a) dispersion (b) scattering (c) atmospheric refraction (d) cannot say Answer: (c) Atmospheric refraction 11. Twinkling of stars and non-twinkling of planets is accounted for by (a) scattering of light (b) dispersion of light (c) atmospheric refraction (d) none of these Answer: (c) Atmospheric refraction 12. In absence of atmosphere, the colour of sky appears (a) blue (b) black (c) red (d) yellow Answer: (b) Black 13. The bluish colour of water in deep sea is due to (a) The presence of algae and other plants found in water (b) Reflection of sky in water (c) Scattering of light (d) Absorbtion of light by sea Answer: (c ) Scattering of light 14. Which image shows the deviation of light in a prism? (a)

Answer: Option (C) 15. The colour of scattered light depends on (a) Size of scattering particles (b) Wavelength of light (c) Both (a) and (b) (d) None of the above Answer Both (a) and (b) 16. Which of the following coloured light has the least speed in glass prism? (a) Violet (b) Yellow (c) Red (d) Green Answer (a) Violet 17. Name the scientist who was the first to use a glass prism to obtain the spectrum of sunlight. (a) Isaac Newton (b) Einstein (c) Kepler (d) Hans Christian Oersted Answer (a) Isaac Newton 18. Assertion (A) : The phenomenon of scattering of light by the colloidal particles gives rise to Tyndall effect. Reason (R): The colour of the scattered light depends on the size of the scattering particles. (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A. (c) A is true but R is false. (d) A is false but R is true. Answer (b) 19. Assertion (A) :Sunlight reaches us without dispersion in the form of white light and not as a component. Reason(R) : Dispersion takes place due to variation of refractive index for different wavelength but in vaccum the speed of light is independent of wavelength and hence vaccum is a non- dispersive medium (a)Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A. (c) A is true but R is false. (d) A is false but R is true. Answer (a) 20. Assertion : Rainbow is an example of the dispersion of sunlight by the water droplets. Reason: light of shorter wavelength is scattered much more than light of longer wavelength (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false. (d) A is false but R is true. Answer (C)

Chapter -LIFE PROCESSES 1. The diagram shows the arrangement of cells inside the leaf of a green plant. (No cell contents are shown). Which cells normally contain chloroplasts? (a) 1 and 2 (b) 1 and 4 (c) 2 and 3 (d) 2 and 4 Ans : (d) 2 and 4 2. Which of the following structures is involved in gaseous exchange in woody stem of a plant? (a) Stomata (b) Lenticel (c) Hydathode (d) Epidermis Ans : (b) Lenticel 3. Which substances are produced by anaerobic respiration in yeast? Carbo Alcohol Lactic Water n Acid dioxid e (a) { { # # (b) { # {# (c) # {# { (d) # # { { Key { = produced, #= not produced. Ans : (a) 4. A plant is kept in the dark for two days. A leaf is used in an experiment to investigate the effect of two factors on photosynthesis as shown in the diagram.

What are the colours of Q and R , when the leaf is tested for starch, using iodine solution? Q R Brown (a) Blue/black Brown (b) Brown Blue/black (c) Blue/black Blue/black (d) Brown Ans : (Q -Brown R-Brown 5. The air consist of 78% Nitrogen . Choose the forms in which most plants absorb nitrogen: 1. Proteins 2. Nitrates and nitrites 3. Urea 4. Atmospheric nitrogen Choose the correct option. (a) 1 and 2 (b) 2 and 3 (c) 3 and 4 (d) 1 and 4 Ans : (b) 2 and 3 6. Only two of the following Statements accurately describe what happens in the mouth. 1. Amylase breaks down large starch molecules into smaller maltose molecules. 2. Chewing increases the surface area of food for digestion. 3. Saliva emulsifies fats into smaller droplets. 4. Teeth breakup large insoluble molecules into smaller soluble molecules which statements are correct? (a) 1 and 2 (b) 2 and 3 (c) 3 and 4 (d) 1 and 4 Ans : (a) 1 and 2 7. The diagram represents a section through the small intestine.

What is the role of the structure labelled X ? (a) They secrete enzymes for digestion (b) They secrete hormones (c) They decrease the surface area of absorption (d) They increase the surface area of absorption Ans : (d) 8. In photosynthesis, which substances are used up, which are produced and which are necessary, but remain unchanged after the reaction? Used up Produced Remain Unchanged (a) Carbo Water Oxygen n Water dioxid e (b) Chlorophyll Carbon dioxide (c) Oxygen Starch Cellulose (d) Water Oxygen Chlorophyll Ans : (d) Used up-Water, Produced-Oxygen, Remain Unchanged-Chlorophyll 9. .Lack of qxygen in muscle often leads to cramps among Athletes . This results due to : (a) conversion of Pyruvate to Ethanol (b) conversion of Pyruvate to Glucose (c) conversion of Glucose to Pyruvate (d) conversion of Pyruvate to Lactic acid 10. The diagram shows part of the human gas exchange system. What are W, X,Y and Z ? Bronchu Bronchio Larynx Trachea s le

(a) W X ZY (b) X Z YW (c) Y W XZ (d) Z Y WX Ans: d 11. The diagram represents a part of human circulatory system. Where is the blood pressure highest? Ans :(b) Q.12. What is the correct route for blood flow in a human? (a) Left atrium \" Left ventricle \" Lungs \" Right ventricle \" Right atrium (b) Left atrium \" Left ventricle \" Right ventricle \" Right atrium \" Lungs (c) Right atrium \" Right ventricle \" Left ventricle \" Left atrium \" Lungs (d) Right atrium \" Right ventricle \" Lungs \" Left atrium \" Left ventricle Ans : (d) Right atrium \" Right ventricle \" Lungs \" Left atrium \" Left ventricle

ASSERTION AND REASONING DIRECTION : The following question consist of two statements - Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below: (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A. (c) A is true but R is false. (d) A is false but R is true. (e) Both Assertion and Reason are false. 1. Assertion : in the daytime, CO2 generated during respiration is used up for photosynthesis. Reason : There is no CO2 release during day. 2. Assertion : Lungs always contain a residual volume of air. Reason : It provides sufficient time for oxygen to be absorbed and for carbon dioxide to be released. 3. Assertion : Transpiration is a necessary evil. Reason : It causes water loss but helps in absorption and upward movement of water and minerals. 4. Assertion : During physiology of excretion, deamination does not take place in liver. Reason : Deamination is a process to make use of excess of amino acids which cannot be incorporated into protoplasm. 5. Assertion : The muscular walls of ventricles are thicker than auricles. Reason : This helps in preventing the back flow of blood. 6. Assertion : The wall off stomach possess thick layers of muscles. Reason : These muscles help in mixing the food with the enzymes presents in the alimentary 7. Assertion : The release of energy in aerobic process is much more than in anaerobic process. Reason : Each glucose molecule produces 2 molecules of ATP and 38 molecules of ATP in aerobic respiration. 8. Assertion : Lipases help in emulsification of fats. Reason : Lipases hydrolyses fats 9. Assertion : Bile is essential for digestion of lipids. Reason : Bile juice contains enzymes. Ans : (c) A is true but R is false

CASE STUDY QUESTIONS Read the following and answer any four questions from (i) to (v) Sumati wanted to see the stars of the night sky. She knows that she needs a telescope to see those distant stars. She finds out that the telescopes, which are made of lenses, are called refracting telescopes and the ones which are made of mirrors are called reflecting telescopes. So she decided to make a refracting telescope. She bought two lenses, L1 and L2, out of which L1 was bigger and L2 was smaller. The larger lens gathers and bends the light, while the smaller lens magnifies the image. Big, thick lenses are more powerful. So to see far away, she needed a big powerful lens. Unfortunately, she realized that a big lens is very heavy. Heavy lenses are hard to make and difficult to hold in the right place. Also since the light is passing through the lens, the surface of the lens has to be extremely smooth. Any flaws in the lens will change the image. It would be like looking through a dirty window. (i) Based on the diagram shown, what kind of lenses would Sumati need to make the telescope? (a) Concave lenses (b) Convex lenses (c) Bifocal lenses Ans: (b) Convex lenses (ii) If the powers of the lenses L1 and L2 are in the ratio of 4:1, what would be the ratio of the focal length of L1 and L2? (a) 4:1 (b) 1:4 (c) 2:1 (d) 1:1

(iii) What is the formula for magnification obtained with a lens? (a) Ratio of height of image to height of object (b) Double the focal length. (c) Inverse of the radius of curvature. (d) Inverse of the object distance. (a) Ratio of height of image to height of object

(iv) Sumati did some preliminary experiment with the lenses and found out that the magnification of the eyepiece (L2) is 3. If in her experiment with L2 she found an image at 24 cm from the lens, at what distance did she put the object? (a) 72 cm (b) 12 cm (c) 8 cm (d) 6 cm ⇒ (v) Sumati bought not-so-thick lenses for the telescope and polished them. What advantages, if any, would she have with her choice of lenses? (a) She will not have any advantage as even thicker lenses would give clearer images. (b) Thicker lenses would have made the telescope easier to handle. (c) Not-so-thick lenses would not make the telescope very heavy and also allow considerable amount of light to pass. (d) Not-so-thick lenses will give her more magnification. Answer:-c. Not-so-thick lenses would not make the telescope very heavy and also allow considerable amount of light to pass.

Read the following and answer any four questions from (i) to (v) Rear view mirror is a device that allows the driver to see rear ward. It usually finds its place at the top of windscreen in side the cabin. This device is one of the most basic but essential safety devices in the vehicle. It provides assistance to the driver during overtaking, parking in reverse gear etc. Generally, vehicles also have a pair of mirrors attached to the body from outside. They are popular as 'side mirrors' or Outer Rear View Mirrors (ORVM) which serve the same purpose. Almost all modern cars mount their side mirrors on the doors-normally at A-pillar rather than the wings (the portion of the body above the wheel well).

A real image of an object is to be obtained. The mirror required for this purpose is : (a) convex mirror (b) concave mirror (c) plane mirror (d) either convex or concave mirror Ans: (b) Concave mirror (i) A boy is standing in front of and close to a special mirror. He finds the image of his head bigger than normal, the middle part of his body of the same size, and his legs smaller than normal. The special mirror is made up of three types of mirrors in the following order from top downwards: (a) Convex, Plane, Concave (b) Plane, Convex, Concave (c) Concave, Plane, Convex (d) Convex, Concave, Plane A plane mirror will produce an image of the same size.A concave mirror will produce a magnified image. A convex mirror will produce a diminished image.Ans: (c) Concave, Plane, Convex (ii) A convex mirror is used: (a) by a dentist (b) for shaving (c) as a rear view mirror in vehicles (d) as a light reflector for obtaining a parallel beam of light Ans: (c) as a rear view mirror in vehicles (iii) Linear magnification (m) produced by a rear view mirror fitted in vehicles : (a) is equal to one (b) is less than one (c) is more than one (d) can be more or less than one depending on the position of object Ans: (b) is less than one

(iv) A concave mirror cannot be used as : (a) a magnifying mirror (b) a torch reflector (c) a dentist‘s mirror (d) a rear view mirror We cannot use a concave mirror as a rearview mirror in motor vehicles. This is because a concave mirror produces inverted images (upside down images)of distant objects. Read the following and answer any four questions from (i) to (v) A ray of light passes from a medium of water to that of air. Light ray will be refracted at the junction separating the two media. Since it passes from a medium of a higher refractive index to that having a lower refractive index, the refracted light ray bends away from the normal. At a specific angle of incidence, the incident ray of light is refracted in such a way that it passes along the surface of the water. This particular angle of incidence is called the critical angle. Here the angle of refraction is 90 degrees. When the angle of incidence is greater than the critical angle, the incident ray is reflected back to the medium. We call this phenomenon total internal reflectionLight is a form of energy that producesin us the sensation of sight. Reflection of light is the phenomenon of bouncing back of light in the same medium on striking the surface of any object. The two laws of reflection are the incident ray, the reflected ray and the normal (atthe point of incidence), all lie in the same plane and the angle of reflection r is always equal to the angle of incidence (i). Refraction of light is the phenomenon of change in the path of light in going from one medium to another.

Mirage is an optical illusion which is responsible for the appearance of the water layer at short distances in a desert or on the road. Mirage is an example of total internal reflection which occurs due to atmospheric refraction. (i) Mirage is caused due to days. (a) total Internal Reflection of light by the various layers of air (b) illusion of the presence of water (c) result of refraction of light from a non-uniform medium (d) during sunny days when driving on a roadway Ans: (a) total Internal Reflection of light by the various layers of air (ii) What is mirage? (a) Depends on the position of object (b) Mirror is concave and the lens is convex (c) Goes straight into the second medium (d) Optical illusion caused due to total Internal Reflection Ans: (d) Optical illusion caused due to total Internal Reflection (iii) What is the condition for total internal reflection? (a) Angle of incidence is less than to critical angle (b) Angle of incidence is equal to critical angle (c) Angle of incidence is greater than to critical angle (d) None of these Ans: (c) Angle of incidence is greater than to critical angle (iv) Mirage is observed mainly during (a) Sunny (b) Winter (c) Spring (d) Hot Ans: (a) Sunny

(v) How a mirage is formed? (a) Between focus and centre of curvature (b) Is formed away from the normal (c) Illusion of the presence of water and is a result of refraction of light from a non-uniform medium (d) Is reflected along the same path Ans: (c) Illusion of the presence of water and is a result of refraction of light from anon-uniform medium

Read the following and answer any four questions from (i) to (v) Convex mirrors are used as rear-view mirrors in vehicles. The image formed in a convex mirror is diminished (ray diagram is shown here) due to which it gives a wide field of view of the traffic behind the vehicle. Consider a convex mirror used on a moving automobile with radius of curvature 2 m and a truck is coming from behind it by maintaining a constant distance of 3.5 m. (i) The distance behind the mirror where the image is formed is (a) 0.28 m (b) 1.5 m (c) 0.78 m

(ii) The nature of the image formed is (b) real and inverted (a) virtual and erect (d) none of these (c) real, erect and enlarged Ans: (a) virtual and erect (iii) The size of the image relative to the size of the truck is (a) 0.30 (b) 0.5 (c) 0.78 (iv) The focal length of the mirror is (a) 0.5 m (b) 1 m (c) 1.5 m

(v) If instead of 3.5 m, truck maintains a distance of 2 m, the image formed will be (a) real, erect and diminished (b) virtual, inverted and diminished (c) real, erect and enlarged (d) virtual, erect and diminished A convex mirror always produces a virtual, erect and diminished image. Ans: (d) virtual, erect and diminished Read the following and answer any four questions from (i) to (v) An overhead projector (OHP), like a film orslide projector; uses light to project an enlarged image on a screen. In the OHP, the source of the image is a page-sized sheet of transparent plastic film (also known as foils) with the imageto be projected either printed or hand- written/drawn. These are placed on the glasssurface of the projector, which has a light source below it and a projecting mirror and lens assembly above it as shown in the figure.

(i) Based on the diagram shown, what kind of lens is used to make the overhead projector? (a) concave lenses (b) convex lenses (c) bifocal lenses (d) flat lenses Ans: (b) convex lenses (ii) The image obtained will be erect and real. How? (a) The image when passed through the lens was erect and was directly obtainedon the screen. (b) The image when passed through the lens was inverted and then it gets reflectedon the mirror to be obtained on the screen. (c) The screen used automatically makes the image erect and real. (d) Both (b) and (c) Ans: (b) The image when passed through the lens was inverted and then it getsreflected on the mirror to be obtained on the screen. (iii) Why is concave mirror used and not convex mirror? (a) because concave mirror can give real image. (b) because convex mirror can give real image. (c) because concave mirror cannot give real image. (d) because convex mirror cannot give virtual image. Ans: (a) because concave mirror can give real image. (iv) If the radius of curvature of concave mirror is 12 cm. Then, the focal length will be : (a) 12 cm (b) 6 cm (c) -24 cm (d) -6 cm We know that f = R/2 = 12/2 = 6 cm But the sign of focal length of concave mirror is negative. Therefore f = -6 cm (v) The power of a convex lens is and that of a concave lens is (b) positive, positive (a) positive, negative (d) negative, negative (c) negative, positive Ans: (a) positive, negative

CASE STUDY QUESTION Read the following and answer any four questions from (i) to (v) A mirror is a surface that reflects a clear image. Images can be of two types: Real image and virtual image. An image that can be formed on the screen is known as a real image and the one which cannot be formed on the screen is known as a virtual image. These images are formed when light falls on a mirror from the object and isreflected back by the mirror on the screen. One useful tool that is frequently used to depict this idea is known as a ray diagram. A ray diagram is a diagram that traces the path that light takes in order for a person to view a point on the image of an object. On the diagram, rays (lines with arrows) are drawn for the incident ray and the reflected ray. A ray diagram used arrow type lines to represent the incident ray and the reflected ray. It also helps to trace the direction in which light travels. (i) Convex mirror always forms, an image : (b) Virtual, inverted and (a) Virtual, erect and enlarged (d) Real, erect and diminished enlarged (c) Virtual, erect and diminished Ans: (c) Virtual, erect and diminished (ii) A convex lens forms the image of sun at : (a) C (b) focus(c) pole(d) between focus and pole When an object is at infinity from a convex lens, then the image formed is : (i) at the focus, (ii) real and inverted, and (iii) much smaller than the object (or highly diminished). Ans: (b) focus