When a glass prism of refracting angle $60^\circ$ is immersed in a liquid,its angle of minimum deviation is $30^\circ$. The critical angle of glass with respect to the liquid medium is......$^\circ$

$A$ thin prism $P_1$ with angle $6^o$ and made from glass of refractive index $1.54$ is combined with another thin prism $P_2$ of refractive index $1.72$ to produce dispersion without deviation. The angle of prism $P_2$ will be:

$A$ plot between the angle of deviation and angle of incidence is shown in the figure. From the graph,one can say that the prism angle is ....... (in $^{\circ}$)

$A$ monochromatic light is incident at a certain angle on an equilateral triangular prism and suffers minimum deviation. If the refractive index of the material of the prism is $\sqrt{3}$,then the angle of incidence is ... $^o$.

$A$ prism has a refractive index $\sqrt{3/2}$ and a refracting angle of $90^o$. Find the minimum deviation produced by the prism in degrees.

$A$ monochromatic ray of light is incident normally on a thin prism of refracting angle $A$. The ray is deviated through an angle $(1.15)^{\circ}$ in passing through the prism. The ray reflected internally from the second face emerges from the first face making an angle of $(6.3)^{\circ}$ with the incident ray. The refractive index of the prism is