(from the article `optics`) ...however, to compare the dispersion with the mean refractive index of the material for some intermediate colour such as the sodium `D` Fraunhofer ...
Found on
http://www.britannica.com/eb/a-z/d/56
a measure of the ability of a substance to disperse light, equal to the quotient of the difference in refractive indices of the substance for two representative wavelengths divided by the difference of the refractive index for an intermediate wavelength and 1. Cf. Abbe number.
Found on
https://www.infoplease.com/dictionary/dispersive-power
No exact match found.
