For a perfectly black body, coefficient of emission is

Question

Aicharya · Accepted Answer

Perfect black body absorption and emission A perfectly black body absorbs all incident radiation regardless of wavelength, giving it an absorption coefficient $a = 1$. Kirchhoff's law establishes that emissivity equals absorptivity at a given wavelength and temperature: $e = a$. Since $a = 1$, the emissivity must also be unity: $e = 1$. A perfectly black body is therefore both a perfect absorber and perfect emitter of radiation. The correct choice is $\boxed{B}$.

For a perfectly black body, coefficient of emission is

Solution