An isosceles prism of angle $A=30^{\circ}$ has one of its surfaces silvered. Light rays falling at an angle of incidence $60^{\circ}$ on the other surface retrace their path after reflection from the silvered surface. The refractive index of the prism material is

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:

The refractive index $(R.I.)$ of a prism is $\sqrt{\frac{7}{3}}$ and the angle of the prism is $60^{\circ}$. The limiting angle of incidence of a ray that will be transmitted through the prism is .....$^{\circ}$

For flint and crown glass prisms,the prism angles are $A'$ and $A$ respectively. When they are used to produce dispersion without deviation,the ratio $A'/A$ will be:

$A$ prism $(\mu=1.5)$ has a refracting angle of $30^{\circ}$. The deviation of a monochromatic ray incident normally on one of its surfaces will be (given,$\sin 48^{\circ} 36^{\prime}=0.75$):

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 $^{\circ}$)