A ray of light, incident on one face of an equilateral prism (made from a material of refractive index μ) undergoes total internal reflection, when its refracted ray falls on the other face of the prism. The angle of incidence, of this ray, equals.
(1) \(sin^{-1}[μ(60°-sin^{-1}\frac{1}{μ})]\)
(2) \(sin^{-1}\left[\frac{(60°-sin^{-1}\frac{1}{μ})}{μ}\right]\)
(3) \(cos^{-1}[μ(60°-sin^{-1}\frac{1}{μ})]\)
(4) \(cos^{-1}\left[\frac{(60°-sin^{-1}\frac{1}{μ})}{μ}\right]\)
