Stefan's Law

Definition: The total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of its thermodynamic temperature. The constant of proportionality, the Stefan-Boltzmann constant has the value 5.6697*10^-8 J s^-1 m^-2 K^-4. The law was discovered by the Austrian physicist Joseph Stefan (1853-93) and theoretically derived by Ludwig Boltzmann.