Question

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

Answer 1

Refractive index of a medium, n_m = Speed of light in vacuum/Speed of light in the medium
Speed of light in vacuum, c = 3 × 10⁸ ms^-1
Refractive index of glass, n_g = 1.50
Speed of light in the glass, v = Speed of light in vacuum/ Refractive index of glass
= c/n_g
=3 × 10⁸/1.50 = 2x 10⁸ ms^-1.