Planck's Law

SPECEXITANCE Calculates the spectral radiant exitance for a black body (W/m^2·µm)

SPECEXITANCE Calculates the spectral radiant exitance for a black body based on Max Planck's law and expressed in (W/m^2·µm)

M = specexitance(LAMBDA, T) computes the spectral radiant exitance based on Max Planck's law based on a given temperature (T, in Kelvin) and wavelength (lamda in micro meter [10^-6 m])

M = specexitance(LAMBDA, T, n) computes the spectral radiant exitance based on Max Planck's law based on a given temperature (T, in Kelvin) and wavelength (lamda in micro meter [10^-6 m]) calulated in a medium
for which the refractive index is not 1.

The function does not exist for lamda == 0.