Thus, if we double the temperature, the amount of energy emitted will increase sixteen times. The radiation striking the surface is either reflected, absorbed, or transmitted. Reflected radiation basically bounces off the surface. Absorbed radiation is the energy the surface captures, just as a sponge soaks up water. The Greek symbol a is used to indicate absorptivity.
Transmitted radiation is energy that passes through.
Due to conservation of energy, all of the radiation must be accounted for. So the sum of the reflected, absorbed, and transmitted radiation must equal the incoming energy. The emitted wavelengths depend on the material properties and temperature. The classical theory of this phenomenon models it according to classical laws of physics. These laws, however, are not sufficient to adequately explain the observed black body spectrum.