The rate of radiant energy emitted is related:
Surface area (A)
The 4th power of the surface temperature (T 4) [T in Kelvin unit!!]
The ability of an object absorb/emit radiant energy, called
emissivity (e)
e is between 0 & 1 for normal substances
and varies with wavelength.
e is 0 for a perfect reflector.
e is 1 for a perfect absorber/emitter ,
which we call “black body”.