A black surface is defined by three criteria: it absorbs all RADIATION that is incident on it emits the MAXIMUM ENERGY possible for a given temperature and wavelength of radiation (according to Planck’s law) the radiation emitted by a blackbody is not DIRECTIONAL (it is a DIFFUSE emitter)

A black surface is the perfect emitter and absorber of radiation. It is an idealized concept (no surface is exactly a black surface), and the characteristics of real surfaces are compared to that of an ideal black surface.

A black surface is defined by three criteria: it absorbs all radiation that is incident on it emits the maximum energy possible for a given temperature and wavelength of radiation (according to Planck’s law) the radiation emitted by a blackbody is not directional (it is a diffuse emitter)

A black surface is the perfect emitter and absorber of radiation. It is an idealized concept (no surface is exactly a black surface), and the characteristics of real surfaces are compared to that of an ideal black surface.