Q. 1. Woolen Clothes Q. 1. Woolen Clothes protect the body from cold protect the body from cold because-because-(a)(a) Cloth is a poor conductor of Cloth is a poor conductor of

heatheat

(b)(b) Cloth is good conductor of heatCloth is good conductor of heat

(c)(c) External heat rays enter into the External heat rays enter into the body through woolen clothesbody through woolen clothes

(d)(d) None of aboveNone of above

Ans. (a)Ans. (a)

Q.2. The owl can see Q.2. The owl can see most clearly in total most clearly in total darkness because-darkness because-

(a)(a)It has squint eyesIt has squint eyes

(b) It has large eyes with orbs (b) It has large eyes with orbs directed forward, giving it directed forward, giving it binocular sightbinocular sight

(c) It has light bulbs in its eyes (c) It has light bulbs in its eyes provided by natureprovided by nature

Ans. (b)Ans. (b)

Q.3 Stainless steel contains-Q.3 Stainless steel contains-

(a) Chromium,Nickel,Iron (a) Chromium,Nickel,Iron and Carbonand Carbon

(b) Nickel,Iron and Carbon(b) Nickel,Iron and Carbon

(c) Iron and Carbon only(c) Iron and Carbon only

(d) Chromium,Iron and (d) Chromium,Iron and CarbonCarbonAns. (d)Ans. (d)

Q.4 The maximum limit of Q.4 The maximum limit of sound beyond which a sound beyond which a person can become deaf person can become deaf is-is-

Ans. (d)Ans. (d)

(a) 55 db(a) 55 db

(b) 75 db(b) 75 db

(c) 85 db(c) 85 db

(d) 120 db(d) 120 db

Too… Too… NoisyNoisy

Q.5 Which gas often Q.5 Which gas often creates more air- creates more air- pollution?pollution?

Ans. (c)Ans. (c)

(a)(a) NitrogenNitrogen

(b)(b) Carbon dioxide Carbon dioxide

(c) Carbon monoxide(c) Carbon monoxide

(d) Oxygen(d) Oxygen

Q.6 During cardiac Q.6 During cardiac failure, which of the failure, which of the following is advised as a following is advised as a first aid?first aid?

Ans. (a)Ans. (a)

(a)(a)Mouth of Mouth resuscitationMouth of Mouth resuscitation

(b) Giving external cardiac (b) Giving external cardiac MassageMassage

(c) Giving cool water to drink(c) Giving cool water to drink

(d) Giving complete body (d) Giving complete body MassageMassage

Q.7 … waves cannot be Q.7 … waves cannot be transmitted through transmitted through vacuum-vacuum-

(a) Light(a) Light

(b) Heat(b) Heat

(c) Sound(c) Sound

(d) Electromagnetic(d) Electromagnetic

Ans. (c)Ans. (c)

Q.8 The small bats can fly Q.8 The small bats can fly in dark because-in dark because-

(a)(a)They can see the objects in They can see the objects in darknessdarkness

(b) They have weak legs land (b) They have weak legs land are likely to be attacked by are likely to be attacked by predatorspredators

(c) They generate flashes of (c) They generate flashes of lightlight

(d) They generate ultrasonic (d) They generate ultrasonic sound wavessound wavesAns. (d)Ans. (d)

(a)(a)Decreases Decreases

(b) Increases(b) Increases

(c) Remains the same(c) Remains the same

(d) Is zero(d) Is zero

Q.9 The time period of a Q.9 The time period of a pendulum on moon-pendulum on moon-

Ans. (b)Ans. (b)

(a)(a)Water expands on freezingWater expands on freezing

(b) Bottle contraits at fruzing (b) Bottle contraits at fruzing pointpoint

(c) Temperature outside the (c) Temperature outside the bottle is ten than that iunde bottle is ten than that iunde

(d) None of above(d) None of above

Q. 10 When water is filled Q. 10 When water is filled in a bottle and is allowed in a bottle and is allowed to freeze, the bottle to freeze, the bottle because –because –

Ans. (a)Ans. (a)

Q.11 Ice packed is saw Q.11 Ice packed is saw dust does not melt dust does not melt quickly. Why?quickly. Why?

Ans.Ans. Saw dust is a bad Saw dust is a bad conductor of heat and conductor of heat and protects the ice from the protects the ice from the external heat and hence external heat and hence from melting away from melting away quickly.quickly.

Q. 12 A boatman pushes Q. 12 A boatman pushes the bank with his pole. the bank with his pole. Why?Why?

Ans.Ans. Action and reaction Action and reaction being equal and being equal and opposite,the bank will push opposite,the bank will push the boat away from it.the boat away from it.

Q. 13 A burning candle Q. 13 A burning candle gets extinguished when gets extinguished when covered with a tumbler. covered with a tumbler. Why?Why?

Ans.Ans. A burning candle gets A burning candle gets extinguished when covered extinguished when covered with a tumbler because the with a tumbler because the supply of oxygen is cut – off supply of oxygen is cut – off and the flame goes out.and the flame goes out.

Q.14 Why do you see Q.14 Why do you see rainbow after rain?rainbow after rain?

Ans.Ans. The water drops The water drops suspended in the suspended in the atmosphere act as prism atmosphere act as prism and disperse light into and disperse light into seven colours.seven colours.

Q,15 A metal tea- pot has Q,15 A metal tea- pot has an ebony handle. Why?an ebony handle. Why?

Ans.Ans. Ebony being bad Ebony being bad conductor of heat, the handle conductor of heat, the handle does not get hot.does not get hot.

Q. 16 Why is it easier to Q. 16 Why is it easier to roll a barrel than to pull it roll a barrel than to pull it along the road?along the road?

Ans.Ans. In winter the water In winter the water vapour contained in the vapour contained in the breath condenses into small breath condenses into small droplets of water, which droplets of water, which become visible. In summer it become visible. In summer it is not so.is not so.

Q. 17 Why is hot soup Q. 17 Why is hot soup more tasty than the colder more tasty than the colder one ?one ?Ans. Ans. As temperature is As temperature is increased, surface tension increased, surface tension decreases and the liquid now decreases and the liquid now occupies more area. Thus the occupies more area. Thus the hot soup occupies more area hot soup occupies more area on the tongue and is, on the tongue and is, therefore, more tasty than therefore, more tasty than the colder one. the colder one.

Q. 18 Why do the stars Q. 18 Why do the stars twinkle?twinkle?

Ans.Ans. The stars seem to The stars seem to twinkle due to two causes. twinkle due to two causes. First the light from the stars First the light from the stars passes through several passes through several mediums; secondly .mediums; secondly .