Question

Light enters from air into glass having refractive index 1.50. What is the speed of light in glass? The speed of light in vacuum is 3 x 108 ms^-1.

Answer 1

Given,n=1.5 and the speed of light in vacuum, c = 3x 10⁸ ms^-1. We know that the refractive index is given by the expression n =c/v where c is the speed of light in vacuum and v is the speed of a light in the given medium (glass). Hence we have
v=c/n=(3x10⁸)/1.5=2.0x10⁸ ms^-1