1261Let a thin capillary tube be replaced with another tube of insufficient length then, we find water?
Ans : will not rise
1262If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same?
Ans : momentum
1263Pick out the scalar quantity?
Ans : pressure
1264Rectifiers are used to convert?
Ans : Alternating current to Direct current
1265Sound waves in air are?
Ans : longitudinal
1266Magnetism at the centre of a bar magnet is?
Ans : zero
1267It is more difficult to walk on a sandy road than on a concrete road because?
Ans : the friction between sand and feet is less than that between concrete and feet
1268Find the maximum velocity for the overturn of a car moving on a circular track of radius 100 m. The co-efficient of friction between the road and tyre is 0.2?
Ans : 14 m/s
1269Lux is the SI unit of?
Ans : intensity of illumination
1270On a rainy day, small oil films on water show brilliant colours. This is due to?
Ans : interference
1271Point A is at a lower electrical potential than point B. An electron between them on the line joining them will?
Ans : move towards B
1272Materials for rain-proof coats and tents owe their water-proof properties to?
Ans : surface tension
1273RADAR is used for?
Ans : detecting and locating the position of objects such as aeroplanes
1274Sound of frequency below 20 Hz is called?
Ans : infrasonic
1275On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because?
Ans : cohesion of mercury is greater than its adhesion with glass
1276Suitable impurities are added to a semiconductor depending on its use. This is done in order to?
Ans : increase its electrical conductivity
1277Stars twinkle because?
Ans : the refractive index of the different layers of the earth's atmosphere changes continuously; consequently the position of the image of a start changes with time
1278It takes much longer to cook food in the hills than in the plains, because?
Ans : in the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100oC causing an increase in cooking time
1279Moment of inertia is?
Ans : tensor
1280Inside an aeroplane, flying at a high altitude,?
Ans : normal atmospheric pressure is maintained by the use of air pumps
1281Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
Ans : Air; water and iron
1282One thousand microns is equal to?
Ans : 10-3m
1283Sound travels at the fastest speed in?
Ans : steel
1284oil raise up the wick in a lamp. The principle involves?
Ans : capillary action phenomenon
1285Superconductors are substances which?
Ans : offer no resistance to the flow of electricity
1286Light travels at the fastest speed in?
Ans : vacuum
1287Railway tracks are banked on curves?
Ans : necessary centripetal force may be obtained from the horizontal component of the weight of the train
1288On a cold day when a room temperature is 15oC, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15oC, because?
Ans : metals are good conductor of heat
1289Sound produced at a point is heard by a person after 5 second, while the same sound is heard by another person after 6 seconds. If the speed of sound is 300 m/s, what could be the maximum and minimum distances between the two persons?
Ans : 3.3 km; 0.30 km
1290Intensity of sound at a point is ____ its distance from the source.?
Ans : inversely proportional to square of
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