posted by Judish .
Two transparent media F and G are separated by a plane boundary. The speed of
light in medium F is 2.0x108 m/sec and in medium G is 2.5x108 m/sec. The critical
angle for which a ray of light from F to G is totally internally reflected is
θ=arcsin (n2/n1) = arcsin(c•v1/v2•c) = arcsin(2•10⁸/2.5•10⁸) = 45.6°