Question

Planks law of radiation according to classiscal theory

Answer 1

According to Kirchhoff's law of thermal radiation, this entails that, for every frequency ν, at thermodynamic equilibrium at temperature T, one has αν,B(T) = εν,B(T) = 1, so that the thermal radiation from a black body is always equal to the full amount specified by Planck's law.

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