What is Stefan’s Law?: Definition with Example

1.    Stefan’s Law: this law is related to radiant energy of a blackbody. According to this law an object that absorbs all radiations fall on it is directly proportional to fourth power to its temperature. This is first important step towards the understanding of blackbody Radiation.

Lets take an example One end of a rod of length 20 cm is inserted in a furnace at 800 K. The sides of the rod are covered with an insulating material and the other end emits radiation like a black body. The temperature of this end is 750 K in the steady state. The temperature of the surrounding air is 300 K.