$A$ thin prism $P_1$ with angle $4^o$ and made from glass of refractive index $1.54$ is combined with another thin prism $P_2$ made from glass of refractive index $1.72$ to produce dispersion without deviation. The angle of prism $P_2$ is......$^o$

Three glass prisms $A, B$ and $C$ of the same refractive index are placed in contact with each other as shown in the figure,with no air gap between the prisms. $A$ monochromatic ray of light $OP$ passes through the prism assembly and emerges as $QR$. The conditions of minimum deviation are satisfied in which prisms?

For an isosceles prism of angle $A$ and refractive index $\mu$,it is found that the angle of minimum deviation $\delta_m=A$. Which of the following options is/are correct?
[$A$] At minimum deviation,the incident angle $i_1$ and the refracting angle $r_1$ at the first refracting surface are related by $r_1=\left(i_1 / 2\right)$.
[$B$] For this prism the refractive index $\mu$ and the angle of prism $A$ are related as $A=\frac{1}{2} \cos ^{-1}(\mu / 2)$.
[$C$] For this prism,the emergent ray at the second surface will be tangential to the surface when the angle of incidence at the first surface is $i_1=\sin ^{-1}\left[\sin A \sqrt{4 \cos ^2 \frac{A}{2}-1}-\cos A\right]$.
[$D$] For the angle of incidence $i_1=A$,the ray inside the prism is parallel to the base of the prism.

$A$ prism has a refracting angle of $30^\circ$ and a refractive index of $\sqrt{2}$. One of its faces is silvered. At what angle of incidence $i$ should a ray be incident on the other face so that it retraces its path after reflection from the silvered face?

$A$ ray of light suffers minimum deviation when incident on a prism having an angle of the prism equal to $60^{\circ}$. The refractive index of the prism material is $\sqrt{2}$. The angle of incidence (in degrees) is . . . . . . .

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 $^{\circ}$)