JEE Main 8 April 2017 Paper Solved Paper

Let the refractive index of a denser medium with respect to a rarer medium be n12 and its critical angle be θC. At an angle of incidence A when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is 90°. Angle A is given by :