$A$ light ray is incident by grazing one of the faces of a prism. After refraction,the ray does not emerge out from the other face. What should be the angle of the prism if the critical angle is $C$?

$A$ prism of crown glass with a prism angle of $9^{\circ}$ and a prism of flint glass are used to make a direct vision spectroscope. If the refractive indices of crown and flint glass are $1.40$ and $1.60$ respectively,then the refracting angle of the flint glass prism will be.....$^{\circ}$

$A$ light ray enters through a right-angled prism at point $P$ with an angle of incidence of $30^{\circ}$ as shown in the figure. It travels through the prism parallel to its base $BC$ and emerges along the face $AC$. The refractive index of the prism is:

$A$ thin prism in air produces the angle of minimum deviation $\delta$. If the prism is immersed in water, the angle of minimum deviation for the same ray is (refractive index of water is $4/3$ and that of glass prism is $3/2$)

$A$ ray incident at ${15^o}$ on one refracting surface of a prism of angle ${60^o}$ suffers a deviation of ${55^o}$. What is the angle of emergence?

The refractive index of glass for red light is $1.520$ and for blue light is $1.525$. Suppose the deviations of red and blue light in a prism of this glass are $D_1$ and $D_2$ respectively. Then .....