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 (in $^{\circ}$)

The cross-section of a prism $(\mu = 1.5)$ is an equilateral triangle. $A$ ray of light is incident perpendicular on one of the faces. The angle of deviation of the ray is......$^o$

For a prism of apex angle $45^o$,it is found that the angle of emergence is $45^o$ for grazing incidence. Calculate the refractive index of the prism.

An isosceles glass prism $\left( \mu = \frac{3}{2} \right)$ has one of its equal faces coated with silver. $A$ ray is normally incident on the other face and is reflected twice and then emerges through the base of the prism perpendicular to it,as shown in the figure. Find the angle $\theta$ of the prism in degrees. (in $^{\circ}$)

$A$ prism having refractive index $\sqrt{2}$ and refracting angle $30^{\circ}$ has one of the refracting surfaces silvered. The beam of light incident on the other refracting surface will retrace its path,if the angle of incidence is $\left[\sin \frac{\pi}{6}=0.5\right]$

The refractive index of the material of a prism is $\sqrt{2}$ and the angle of the prism is $30^{\circ}$. One of the two refracting surfaces of the prism is made a mirror inwards,by silver coating. $A$ beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is (in $^{\circ}$)