## Physics (Objective) (Pages :44) <<< Back

• 1261 Let a thin capillary tube be replaced with another tube of insufficient length then, we find water?

Ans : will not rise
• 1262 If 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
• 1263 Pick out the scalar quantity?

Ans : pressure
• 1264 Rectifiers are used to convert?

Ans : Alternating current to Direct current
• 1265 Sound waves in air are?

Ans : longitudinal
• 1266 Magnetism at the centre of a bar magnet is?

Ans : zero
• 1267 It 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
• 1268 Find 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
• 1269 Lux is the SI unit of?

Ans : intensity of illumination
• 1270 On a rainy day, small oil films on water show brilliant colours. This is due to?

Ans : interference
• 1271 Point A is at a lower electrical potential than point B. An electron between them on the line joining them will?

Ans : move towards B
• 1272 Materials for rain-proof coats and tents owe their water-proof properties to?

Ans : surface tension
• 1273 RADAR is used for?

Ans : detecting and locating the position of objects such as aeroplanes
• 1274 Sound of frequency below 20 Hz is called?

Ans : infrasonic
• 1275 On 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
• 1276 Suitable impurities are added to a semiconductor depending on its use. This is done in order to?

Ans : increase its electrical conductivity
• 1277 Stars 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
• 1278 It 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
• 1279 Moment of inertia is?

Ans : tensor
• 1280 Inside an aeroplane, flying at a high altitude,?

Ans : normal atmospheric pressure is maintained by the use of air pumps
• 1281 Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?

Ans : Air; water and iron
• 1282 One thousand microns is equal to?

Ans : 10-3m
• 1283 Sound travels at the fastest speed in?

Ans : steel
• 1284 oil raise up the wick in a lamp. The principle involves?

Ans : capillary action phenomenon
• 1285 Superconductors are substances which?

Ans : offer no resistance to the flow of electricity
• 1286 Light travels at the fastest speed in?

Ans : vacuum
• 1287 Railway tracks are banked on curves?

Ans : necessary centripetal force may be obtained from the horizontal component of the weight of the train
• 1288 On 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
• 1289 Sound 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
• 1290 Intensity of sound at a point is ____ its distance from the source.?

Ans : inversely proportional to square of

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