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Four indentical calorimeters painted in different colours, are heated to same temperature and then allowed to cool in vacuum. Which will cool fastest ?
(a)One which is painted bright
(b)One which is painted this white
(c)One which is painted thick black
(d)One which is painted bright white

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Important Questions on Heat Transfer
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A body cools from 60ºC to 50ºC in 10 minutes, If the room temperature is 25°C and assuming Newtons' cooing law holds good, the temperature of the body at the end or next 10 minutes is :

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Compare to a person with white skin, another person with dark skin will experience:

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We consider the radiation emitted by the human body. Which of the following statements is true?

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Shown below are the black body radiation curves at temperatures T1 and T2 (T2 > T1). Which of the following plots is correct :-

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The radii of two spheres made of same metal are r and 2r. These are heated to the same temperature and placed in the same surrounding. The ratio of rates of decrease of their temperature will be

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If E is the total energy emitted by a body at a temperature TK and is the maximum spectral energy emitted by it at the same temperature, then-

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If be the emissive power and absorption power respectively of a body and be the emissive power of an ideal black body, then from Kirchhoff's laws

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A liquid takes to cool from to . How much time will it take to cool from to ? The temperature of the surroundings is .
