(d) Size of the pressure
Ans : (d)
142. Mica is used in an electric iron because it is a: [CBI 1991]
       (a) good conductor of electricity
       (b) bad conductor of electricity
       (c) good conductor of heat
       (d) bad conductor of heat
Ans : (b)
143. Tiredness is felt on the top of the mountains because of:
       (a) high temperature
       (b) low temperature
       (c) high pressure outside the body
       (d) low pressure outside the body
Ans : (d)
144. Oil rises up the wick in a lamp because: [RRB 1993]
       (a) oil is very light
       (b) of the diffusion of oil through the wick
       (c) of the surface tension phenomenon
       (d) of the capillary action phenomenon
Ans : (d)
145. Clear nights are cooler than cloudy nights because of:
       (a) conduction
       (b) condensation
       (c) radiation
       (d) isolation
Ans : (c)
146. Nights are cooler in the deserts because:
       (a) sand radiates heat less quickly as compared to earth
       (b) the sky is generally clear
       (c) sand radiates heat more quickly as compared to earth
       (d) the sky is generally cloudy
Ans : (c)
147. Water pipes are apt to burst in cold weather because: [RRB 1993]
       (a) heavy pressure is exerted by snow
       (b) they contact in cold
       (c) the water in the pipe turns into ice and expands
       (d) the water in the pipe cannot evaporate
Ans : (c)
148. Why is a cyclist required to bend inwards while moving in a circular path?
       (a) To keep the vehicle on the road
       (b) To make the centre of gravity fall within the base
       (c) To produce the necessary centripetal force required to keep him moving in a curved path
       (d) None of the above
Ans : (c)