Question

What is Total Internal Reflection?

Answer

Total Internal Reflection - In this situation, when the angle of incidence exceeds a particular angle, the incident ray comes back into first medium (denser medium). This angle is called critical angle (θ_C). This whole phenomenon is called total internal reflection. At critical angle, there is no refracted ray found because ∠r = 90° sinθ_C/sin90° = μ_rarer/μ_denser = μ_r/μ_d ⇒ sinθ_C = μ_r/μ_d ⇒ [θ_C = sin^-1 (μ_r/μ_d)] where, μ_r = Refractive index of rarer medium and μ_d = Refractive index of denser medium