# State the Stefan ? Boltzmann law of radiation. Express its mathematical form.

The Stephan-Boltzmann Law describes the power radiated a body that absorbs all radiation that falls on its surface in terms on its temperature. The radiation energy per unit time from a black body is proportional to the fourth power of the absolute temperature and can be expressed with Stefan-Boltzmann Law as: The Stefan-Boltzmann Constant.

Radiate energy = (Emissivity) (Stefan-Boltzmann constant) (Temperature)^{4} (Area)

The equation is:

P = є σ T^{4} A

P: Radiate energy

σ: The Stefan-Boltzmann Constant

T: absolute temperature in Kelvin

є: Emissivity of the material.

A: Area of the emitting body

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