A ray of light is incident at an angle of incidence i, on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is μ, then the angle of incidence i, is nearly equal to

Options

(a) μA
(b) μA/2
(c) A/μ
(d) A/2μ

Correct Answer:

μA

Explanation:

For normally emerge e =0
Therefore r₂ = 0 and r₁ = A
Snell’s Law for Incident ray’s
1 sin i = µ sin r₁ = µ sin A
For small angle i = µA