161. It takes much longer to cook food in the hills than in the plains, because
- A. in the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100
- B. due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longe
- C. in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere
- D. in the hills the humidity is high and therefore a lot of heat is absorbed by the atmosphere leaving very little heat for cooking
- Check Answer | Discussion
- A. absorption of sunlight in minute water droplets
- B. diffusion of sunlight through water droplets
- C. ionisation of water deposits
- D. refraction and reflection of sunlight by water droplets
- Check Answer | Discussion
163. Large transformers, when used for some time, become very hot and are cooled by circulating oil. The heating of the transformer is due to
- A. the heating effect of current alone
- B. hysteresis loss alone
- C. both the heating effect of current and hysteresis loss
- D. intense sunlight at noon
- Check Answer | Discussion
164. Supersonic plane fly with the speed
165. One thousand microns is equal to
- A. locating submerged submarines
- B. receiving a signals in a radio receiver
- C. locating geostationary satellites
- D. detecting and locating the position of objects such as aeroplanes
- Check Answer | Discussion
167. It is easier to roll a barrel full of coal tar than to pull it because
- A. the full weight of the barrel comes into play when it is pulled
- B. the rolling friction is much less than the sliding friction
- C. more surface area of the barrel is in contact with the road when it is pulled
- D. coal tar is a liquid and it flows in the barrel when it is rolled
- Check Answer | Discussion
168. Rectifiers are used to convert
- A. Direct current to Alternating current
- B. Alternating current to Direct current
- C. high voltage to low voltage
- D. low voltage to high voltage
- Check Answer | Discussion
169. Light Emitting Diodes (LED) is used in fancy electronic devices such as toys emit
170. ML2T-2 is the dimensional formula for
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