Question

Refractive index of a transparent material is ______.

Options

• same for all colours

• maximum for violet colour

• minimum for violet colour

• maximum for red colour

Answer 1

Refractive index of a transparent material is maximum for violet colour.

Explanation:

In a transparent dispersive material, the velocity of violet light is the least among all colours, so its refractive index is the highest according to the relation n = `c/v`, where (c) is the speed of light in a vacuum and (v) is the speed in the medium. Hence, refractive index is maximum for violet light and minimum for red light. This phenomenon causes violet light to bend more in a prism compared to red light.