Stefan-Boltzmann law of radiation:
After careful analysis of the results of a few experiments by scientists Dulong Petit and Tyndall, famous physicists Joseph Stefan formulated the relation connecting the amount of radiation emitted by a body and the temperature of the body. This law is known as Stefan’s law. The law states that the total heat radiated (E) from a body at an absolute temperature T is directly proportional to the fourth power of the absolute temperature of the body.
Later in 1884 Boltzmann theoretically proved the law from thermodynamical considerations and established that the law is valid only for black body radiation. The law states that the total radiant energy emitted per second per unit surface area of a perfectly black body is directly proportional to the fourth power of its absolute temperature. This law is also known as Stefan-Boltzmann law.