Question

A ray of light travelling from air is incident on a glass slab. How is the refractive index of
glass calculated in terms of the speed of light in air and glass?

Answer 1

Explanation:

In passing through a rectangular glass slab, a ray of light undergoes two refractions and emerges from opposite side of the slab in a direction parallel to the direction of incidence of light. The emergent ray is , however, displaced laterally.

Glass refractive index is defined as the ratio between the speed of light in the vacuum and the speed of light in the glass.

$Refractive index of glass (ng) = \frac{Speed of light in vacuum}{Speed of light in the glass}$