Question

Solve this:
Q.(b) What is meant by the term absolute refractive index? The speed of light in a transparent medium is 0.6 times that the speed in vacuum. Find the refractive index of the medium.

Answer 1

Dear Student ,

If medium 1 is vacuum or air, then the refractive index of medium 2 is considered with respect to vacuum. This is called the absolute refractive index of the medium. It is simply represented as n₂

If c is the speed of light in air and v is the speed of light in the medium, then, the refractive

index of the medium n_m is given by

n_m = c/v

As by formula:- μ=$\frac{c}{v}$ ......(1) where c is the velocity of light in vaccuum & v is the velocity of light in medium.
As by question:-v=0.6 of c
Applying the value of v in equation (1):-
μ=$\frac{c}{0.6c}$
μ=$\frac{1}{0.6}$
=1.6

Regards