The critical angle for refraction from medium 1 to air is θ1 and that from medium 2 to air is θ2. If medium2 is …..

Q. The critical angle for refraction from medium 1 to air is θ1 and that from medium 2 to air is θ2 . If medium 2 is denser than medium 1. Find the critical angle for refraction from medium 2 to medium 1.

(a) sin^-1 (sinθ₂/sinθ₁ )

(b) sin^-1 (sinθ₁/sinθ₂ )

(c) sin^-1 (sinθ₂ )

(d) sin^-1 (sinθ₁ )

Ans: (a)

Sol:

sinθ₁ = 1/μ₁ and sinθ₂ = 1/μ₂

sinθ = 1/¹μ₂ = μ₁/μ₂ = sinθ₂ / sinθ₁

θ=sin^-1(sinθ₂ / sinθ₁)