. Three objects coloured black, gray and white can withstand hostile conditions


upto 2800°C. These objects are thrown into a furnace where each of them attains a temperature of 2000°C. Which object will glow brightest?

(a)  The white object

(b)   The black object               

(c)  All glow with equal brightness    

(d)  Gray object

Best Answer

Answer: (b)

Solution : An ideal black body absorbs all the radiations incident upon it and has an emissivity equal to 1. If a black body and an identical another body are kept at the same temperature, then the black body will radiate maximum power.

Hence, the black object at a temperature of 2000°C will glow brightest.

 

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