law giving the spectral distribution of radiance of a Planckian radiator as a function of wavelength and temperature
Note 1 to entry: The formula is sometimes written with instead of , where
Note 2 to entry: For a detector in a medium of refractive index
Note 3 to entry: Planck's law can also be expressed to give the spectral distribution of radiant exitance,
Note 4 to entry: Both quantities (radiance and radiant exitance) apply to the unpolarized radiation as emitted.
Note 5 to entry: For the up-to-date values of the Planck constant,
Note 6 to entry: This entry was numbered 845-04-05 in IEC 60050-845:1987.
Note 7 to entry: This entry was numbered 17-958 in CIE S 017:2011.