Stefan's -Boltzmann Law

This law states that the total amount of radiant energy emitted by a black body per second per unit area is directly proportional to the fourth power of its absoliute temperature i.e. E∝T⁴ or E=𝜎T⁴ where 𝜎 is called Stefans constant. It has a value of 5.67 x 10⁻⁸ Wm⁻²K⁻⁴. This law is strictly true only when the medium sorrounding the black body is vacuum.

The same law was established later by Boltzmann theoretically from thermodynamical considerations. Hence, this law is known as Stefan-Boltzmann law.

This law is true only when medium sorrounding the body is vacuum.



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