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| 87)Perspiration (sweat) is maximum when | |||
| temperature is high and air is humid | temperature is high and air is dry | ||
| temperature is low and air is humid | temperature is low and air is dry | ||
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| 88)Scalding with boiling water is less severe than scalding by steam because | |||
| steam is at higher temperature that boiling water | steam can penetrate the skin | ||
| steam contains more energy than boiling water | steam is in higher pressure | ||
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| 89)A person feels cold after a deep in sea water because | |||
| deposition of salt on the body | convection current | ||
| the evaporation of water on the body | the difference in temperature between land and sea | ||
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| 90)Even in a hot day also the surface water of a pond remains cool because | |||
| the heat absorbs at the surface transmitted downwards | water evaporates at the surface and it causes cooling | ||
| water at the bottom remains cool and rises up | none of these | ||
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| 91)The capacity of holding water vapour in the atmosphere | |||
| decreases as temperature increases | increases as temperature increases | ||
| increases as temperature decreases | decreases as temperature decreases | ||
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| 92)The boiling point of water depends on | |||
| the atmospheric pressure | the material of the container | ||
| relative humidity | none of these | ||
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| 93)Cooking some thing on a hill take long time than in the plain because | |||
| due to the atmospheric pressure on the hill boiling point of water rises and takes long time to cook | on the hill atmospheric pressure is low so water boils at lower temperature so it takes long time to cook | ||
| on the hill atmospheric temperature is low so lot of heat goes to the atmosphere so it takes long time to cook | humid air on the hill takes away the heat so it takes long time to cook | ||
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| 94)Food is cooked faster in pressure cooker because | |||
| heat can not escape | steam is hotter than boiling water | ||
| due to the high pressure water boils at high temperature | in the cooker water boils at very low temperature | ||
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| 95)Why a solar cooker has a glass cover? | |||
| because glass is good conductor of heat and cheap | because glass allow light to pass through but does not allow heat radiation to pass through | ||
| because through one can see the food cooking | because glass does not absorb heat radiation | ||
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| 96)Light waves are different from sound waves | |||
| Sound waves are not electromagnetic but light waves are electromagnetic. | Light waves travel in equal speed in all media but sound waves do not | ||
| Light can travel through water but sound can not | none of these | ||
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| 97)Which of the following has longest wave length? | |||
| light rays | ultra-violet ray | ||
| infrared ray | gamma rays | ||
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| 98)Which layer of the atmosphere is responsible for reflecting radio waves to the earth? | |||
| stretosphere | troposphere | ||
| messosphere | ionosphere | ||
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| 99)Quality of radio reception increases slightly during night because | |||
| No noise during night | sun light affects the radio signal | ||
| intensity of radio signal is more at night | earth magnetic field does not affect the radio signal at night | ||
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| 100)Television signal is limited to a particular distance because | |||
| of the earth carvature | of weakening of signal beyond the distance | ||
| of absorption of signal in the air | of the small antenna | ||
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| 101)Generally radar is used for | |||
| detecting and finding position of aeroplane | studying sun spot | ||
| studying weather | studying earthquake | ||
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