A ray of light is incident normally on one face of `30^(@) - 60^(@) - 90^(@)` prism of refractive index 5/3 immersed in water of refractive index 4/3 as shown in figure .

Options

A. the exit angle `theta_2` of the ray is `sin^(-1) (5//8)`
B. the exit anlge `theta_2` of the ray is `sin^(-1) (5//4 sqrt3)`
C. total internal reflection at point P ceases if the refractive index of water is increased to `5//2 sqrt3` dissolving some substance.
D. Total internal reflection at point P ceases if the refractive index of water is increased to 5/6 by dissolving some substance.

Answer

A, C