Question

A ray of light enters a rectangular glass slab of refractive index 1.5. It is found that the




ray emerges from the opposite face of the slab without being displaced. If its speed in




air is 3 x 108




ms-1 then what is its speed in glass?

Answer 1

The speed of the light is 3×10^8.

and the refrective index of glass is(c) =1.5

The refrective index of light in vacuum is(v) =3

hence speed of light in glass =v/c

3/1.5=2 m/s