What is a black body ?

(A) : A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation. ( R) : All metals act as a black body.

The best laboratory approximation to an ideal black body is

The ratio of energies of emtiied radiation by a black body at 600 K and 900 K when the surrounding temperature is 300, is

If the absolute temperature of a black body is doubled then Energy radiated by it in a given time intervaL will be increased by

The temperature of an isolated black body falls from T_(1) to T_(2) in time t. Let C be a constant, then

The power radiated by a black body is P, and it radiates maximum energy around thee wavelength lambda_(0) . If the temperature of the black body is now changed so that it radiates maximum energy around a wavelength 3lambda_(0)//4 , the power radiated by it will increase by a factor of