Black body radiation is white and a hole in the cavity of a radiator is a black body. Explain.

Explanation

A black body absorbs radiations of all wavelenghts falling on it. When it is heated to a suitable temperature it emits radiations of all wavelengths . The combination of radiations of all visible wavelength makes white light. Hence the black body radiation is white.
A hole in the cavity of a radiator does not reflect any radiation incident on it but absorbs them all. so it works as a black body.