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

We know that:

Refractive index of glass = (Speed of light in air (or vacuum))/(Speed of light in glass)

1.50 = (3×10⁸)/(Speed of light in glass)

Or, Speed of light in glass = = 2×10⁸ ms^-1

Thus, the speed of light in glass is 2×10⁸ ms^-1 (or 2×10⁸ m/s).