The Stefan–Boltzmann law is used to calculate the radiation heat transfer rate.

It is given by,

The above equation is valid only when applied to black bodies. The surface emissivity of black bodies is 1. For non-black bodies, the surface emissivity is less than 1.

The Stefan–Boltzmann law is used to calculate the radiation heat transfer rate.

It is given by,

The above equation is valid only when applied to black bodies. The surface emissivity of black bodies is 1. For non-black bodies, the surface emissivity is less than 1.