Question

When light is incident on a glass slab, the incident ray, refracted ray and the emergent ray are in three media A, B and C. If n₁, n₂ and n₃ are the refractive indices of A, B and C respectively and the emergent ray is parallel to the incident ray, which of the following is true ?

(a) n₁ < n₂ < n₃

(b) n₁ > n₂ > n₃

(c) n₁ < n₂ = n₃

(d) n₁ = n₃ < n₂

Answer 1

Correct answer is (d) n₁ = n₃ < n₂ 

Medium A and C in air, therefore, n₁ = n₃, but glass slab is of higher refractive index.

∴ n₁ = n₃ < n₂