General Knowledge :: Physics
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On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
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Suitable impurities are added to a semiconductor depending on its use. This is done in order to
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Stars twinkle because
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It takes much longer to cook food in the hills than in the plains, because
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Of the following natural phenomena, tell which one known in Sanskrit as 'deer's thirst'?
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Inside an aeroplane, flying at a high altitude,
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Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
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A.
the intensity of light emitted by them changes with time
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B.
the distance of the stars from the earth changes with time
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C.
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
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D.
the light from the star is scattered by the dust particles and air molecules in the earth's atmosphere
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A.
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 |
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B.
due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longer to boil |
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C.
in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere |
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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 |