Find the maximum angle of refraction when a light ray is refracted from glass $(\mu =1.50)$ to air.

A point source is placed at a depth $h$ below the surface of the water (Refractive index$=\mu$).

(a) Show that the light escapes through a circular area on the water surface with its centre directly above the point source.

(b) Find the angle subtended by a radius of the area on the source. 

A container contains water up to a height of $20 \mathrm{cm}$ and there is a point source at the centre of the bottom of the container. A rubber ring of radius $r$ floats centrally on the water. The ceiling of the room is $2.0 \mathrm{m}$ above the water surface.

(a) Find the radius of the shadow of the radius of the ring formed on the ceiling if $r=15 \mathrm{cm}$.

(b) Find the maximum value of $r$ for which the shadow of the ring is formed on the ceiling. Refractive index of water$=\frac{4}{3}$.

Find the angle of deviation suffered by the light ray shown in the figure. The refractive index is $\mu =1.5$ for the prism material.