Question

When a ray of light is incident at an angle of 30° on an equilateral glass prism, it suffers minimum deviation. The angle between the emergent ray and the second refracting surface of the prism is ______.

Options

• 60°

• 45°

• 30°

• 0°

Answer 1

When a ray of light is incident at an angle of 30° on an equilateral glass prism, it suffers minimum deviation. The angle between the emergent ray and the second refracting surface of the prism is 60°.

Explanation:

i = 30°

under minimum deviation condition i₁ = i₂ = e

∴ e = 30°

∴ emergent ray makes an angle of 60° with the surface.