A liquid takes 5 minutes to cool from 80°C to 50°C. how much time it will take to cool from 60°C to 30°C, if the temperature of the surrounding is 20°C?
A person with dark skin as compared to a person with white skin will experience |
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The good absorber of heat are |
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For a given body at a particular temperature, its coefficients of reflection and transmission are 0.63 and 0.21 respectively. Then its coefficient of emission at the same temperature will be |
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A body of surface area 25 × 10-3 m2 emits 0.4 Kcal of heat in 20 s at 50°C. What is the emissive power of the body at that temperature? |
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The unit of Stefa’s constant is |
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The solar constant for the earth is about 1.8 J/m2/S. what is the solar constant for a black body situated on a planet which is situated at a distance of 0.3 times the distance of the earth from the sun? |
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The velocity of thermal radiation (V) is related to the velocity of light (C) as |
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512 calories of radiation is incident on a body. It absorbs 220 calories the coefficient of emission is |
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If a = 0.72, r = 0.24, then value of t is |
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A liquid takes 5 minutes to cool from 80°C to 50°C. how much time it will take to cool from 60°C to 30°C, if the temperature of the surrounding is 20°C? |
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