Question

Q. 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 m/s.​

Answer 1

Let's denote refractive index of glass by 'n(g)'

and, Speed of light in glass by 'v(g)'

We know that, refractive index of a medium is equal to the ratio of speed of light in vacuum(c) to the speed of light in that medium.

Thus,

n(g) = c/v(g)

1.50 = 3×10^8/v(g)

=> v(g) = (3/1.5) ×10^8

=> v(g) = 2×10^8 m/s

Hence, speed of light in glass is 2×10^8 m/s