A black body radiates energy at the rate of 1×105 J/(sm)2 at a temperature of 227°C. The temperature to which it must be heated so that it radiates energy at the rate of 1×109 J/(sm)2.

In thermodynamics, absorption and emission are two of the four main methods of heat transfer:
Absorption: The spectra produced when electrons of an atom absorb energy
Emission: The spectra produced when electrons release energy