EMISSIVITY
Definition
An <EMISSIVITY> is a <RATIO> of the energy radiated from a material-s surface to that radiated from a blackbody (a perfect emitter) at the same temperature and wavelength and under the same viewing conditions. It is given by epsilon = M/M_b where M is the radiant exitance of a thermal radiator and M_b is the radiant exitance of a blackbody at the same <TEMPERATURE>