| Definition: | quotient of the radiant or luminous or photon quantity dX (λ) contained in an elementary range dλ of wavelength at the wavelength λ, by that range
X
unit: [X] ⋅ m−1, e.g. W ⋅ m−1, lm ⋅ m−1, etc.
NOTE 1 – The term spectral distribution is to be preferred when dealing with the function Xλ (λ) over a wide range of wavelengths, not at a particular wavelength.
NOTE 2 – See the note to 845-01-16.
|