. 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
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.