Refraction of Light at Plane Surfaces — Question 10

The factors on which the refractive index of a medium depends are as follows —

(i) Nature of the medium (on the basis of speed of light) — Less the speed of light in the medium as compared to that in air, more is the refractive index of the medium.

We know that,

$μ = \dfrac{\text{Speed of light in vacuum or air (c) }}{\text {Speed of light in glass (V)}} \\[0.5em]$

V_glass = 2 x 10 ⁸ ms^-1, μ_glass = 1.5

V_water = 2.25 x 10 ⁸ ms^-1, μ_water = 1.33

(ii) Physical condition such as temperature — With an increase in temperature, the speed of light in medium increases, so the refractive index of the medium decreases.