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Earn 100
The temperature of a perfect black body is 727ºC and its area is 0.1 m2. If stefan's constant is 5.67 × 10–8 watt/m2-K4, then heat radiated by it in 1 minute is :
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Important Questions on Heat Transfer
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A black body radiates energy at the rate of at a high temperature . When the temperature is reduced to , the radiant energy becomes where _____.
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In solar spectrum fraunhoffer's lines are presents because:
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On reducing temperature of surface to one third, amount of radiation becomes:-
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The absorptive power of a perfectly black body is
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A black body emits radiation of maximum intensity at 5000 when its temperature is 1227ºC. If its temperature is increased by 1000ºC then the maximum intensity of emitted radiation will be at :
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Three objects coloured black, grey and white can withstand hostile conditions up to . These objects are thrown into a furnace where each of them attains a temperature of . Which object will glow brightest?
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A black body, at a temperature of 227ºC radiates heat at a rate of 7 cam cm–2 s–1. At a temperature of 727ºC, the rate of heat radiated in the same units will be :-
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A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat in time . The metallic rod is melted, and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod, when placed in thermal contact with the two reservoirs in time ?
