One of the refractive surfaces of a prism of angle $30^{\circ}$ is silvered. $A$ ray of light incident at an angle of $60^{\circ}$ retraces its path. The refractive index of the material of the prism is:

When a ray of light is incident normally on one refracting surface of an equilateral prism (Refractive index of the material of the prism $= 1.5$),what happens to the ray at the second refracting surface?

If the angle of minimum deviation produced by an equilateral prism is equal to the angle of the prism,then the refractive index of the material of the prism is nearly

In the visible region,the dispersive powers and the mean angular deviations for crown and flint glass prisms are $\omega, \omega^{\prime}$ and $d, d^{\prime}$ respectively. The condition for obtaining dispersion without deviation,when the two prisms are combined,is:

$A$ prism with a refractive index of $1.53$ is placed in water with a refractive index of $1.33$. If the angle of the prism is $60^{\circ}$,then the angle of minimum deviation in water will be ....$^{\circ}$.

The refractive index of a transparent liquid filled in an equilateral hollow prism is $\sqrt{2}$. The angle of minimum deviation for the liquid will be (in $^{\circ}$)