As shown in figure light P enters to slab at an angle 60° with normal and inside slab Q makes total internal reflection. Find minimum refractive index of slab.

Figure shows a mixture of blue, green and red coloured rays incident normally on a right angled prism. The critical angles of the material of the prism for red, green and blue are 46°, 44° and 43° respectively. The arrangement will separate.

A light ray travelling in a glass medium is incident on glass-air interface at an angle of incidence q. The reflected (R) and transmitted (T) intensities, both as function of q, are plotted. The correct figure is : (θc = critical angle)