Question

A light ray enters from medium a to medium b the refractive index of medium b relative to a will be

Answer 1

Answer:

refractive index will be speed of light in medium B upon speed of light in medium a

Answer 2

Relative refractive index:

• When a light ray travels from medium 'a' to medium 'b', the refractive index of 'b' relative to 'a' is defined as the ratio of velocity of light in medium 'a' to the velocity of light in medium 'b'.
• It is given as

                       $n_{ba}=\frac{n_{b}}{n_{a}}$

                       $n_{ba}=\frac{c/v_{b}}{c/v_{a}}$

                       $n_{ba}=\frac{v_{a}}{v_{b}}$

        Where,

                      $n_{b}=$ refractive index of medium 'b'

                      $n_{a}=$ refractive index of medium 'a'

                       $v_{a}=$ velocity of light in medium 'a'

                      $v_{b}=$ velocity of light in medium 'b'

                       c = velocity of light in vacuum/air

• If the light ray bends towards normal after refraction, then the relative refractive index($n_{ba}$) will be greater than unity.
• If the light ray bends away from the normal after refraction, then their relative refractive index($n_{ba}$) will be less than unity.