Light takes t1 sec to travel a distance x cm in vacuum and takes t2 sec to travel 10x cm in a medium. The critical angle…..

Q.Light takes t1 sec to travel a distance x cm in vacuum and takes t2 sec to travel 10x cm in a medium. The critical angle corresponding to the media is

(a)sin^-1(10t₁/t₂)

(b) sin^-1(t₂/(10t₁ ))

(c) sin^-1(10t₂/t1 )

(d) sin^-1(t₁/(10t₂ ))

Ans:(a)

Sol: t₁ = x/c , t₂ = 10x/(c/μ ) = 10xμ/c

Hence , t₂ = 10μt₁ => μ= t₂/10t₁

sinθ = 1/μ =10t₁/t₂

θ = sin⁻¹(10t₁/t₂)