Define absolute refractive index. Absolute refractive indices of medium ‘A’ and medium ‘B’ are and ‘nb’ respectively, what is the refractive index of medium ‘B’ with respect to medium ‘A’? How does the velocity of light vary with change in the optical density of the media?
Absolute refractive index of a medium is defined as the ratio of the velocity of light in vacuum to the velocity of light in the medium. If c is the velocity of light in vacuum and v in the medium, then n = c/v.
If n_{a} and n_{b} are the absolute refractive indices of the medium A and B respectively, then
n_{a} = c/v_{a} and n_{b} = c/v_{b}, then
