Question

A ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence and each of these is equal to `3/4` of the angle of the prism. The angle of deviation is:

विकल्प

• 45°

• 29°

• 30°

• 20°

Answer 1

30°

Explanation:

Given Data:

The angle of the prism (A) = 60°

Angle of incidence (i) = Angle of emergence (e)

Each angle is equal to `3/4` of the angle of the prism (A).

Calculation:

i = e = `3/4 xx A`

= `3/4 xx 60°`

= 45°

Use the standard prism formula relating the angles:

A + δ = i + e

60° + δ + 45° + 45°

60° + δ = 90°

δ = 90° − 60°

δ = 30°