A rectengular glass slab ABCD of refractive index n_1 is immersed in water of refractive index `n_2(n_1gtn_2)`. A ray of light is incident at the surface AB of the slab as shown. The maximum value of the angle of incidence `alpha_max` such that the ray comes out only from the other surface CD is given by

Options

A. `sin^-1[(n_1)/(n_2)cos(sin^-1((n_2)/(n_2)))]`
B. `sin^-1[n_1cos(sin^-1((1)/(n_2)))]`
C. `sin^-1((n_1)/(n_2))`
D. sin^-1((n_2)/(n_2))`

Answer

A