In the diagram,a prism of angle $30^o$ is used. $A$ ray $PQ$ is incident as shown. An emergent ray $RS$ emerges perpendicular to the second face. The angle of deviation is.....$^o$

$A$ light ray is incident on a prism of angle $A = 60^{\circ}$ and refractive index $\mu = \sqrt{2}$. The angle of incidence at which the emergent ray grazes the surface is given by:

The variation of the refractive index of a crown glass thin prism with the wavelength of the incident light is shown. Which of the following graphs is the correct one,if $D_m$ is the angle of minimum deviation?

$A$ ray of light passing through an equilateral prism has a velocity of $2.12 \times 10^8 \text{ m/s}$ in the prism material. The minimum angle of deviation is . . . . . . degrees.

$A$ graph is plotted between angle of deviation $(\delta)$ and angle of incidence $(i)$ for a prism. The nearly correct graph is

One side of an equilateral prism is painted by a transparent material of refractive index $n_2$. The refractive index of the prism is $1.6$. The minimum value of $n_2$ required for total internal reflection from the painted face is . . . . . . .