$A$ thin prism $P_1$ with an angle $6^{\circ}$ and made of glass of refractive index $1.54$ is combined with another prism $P_2$ made from glass of refractive index $1.72$ to produce dispersion without average deviation. The angle of prism $P_2$ is $........{}^{\circ}$

The angle of minimum deviation is equal to the angle of the equilateral prism. At what angle of incidence $i$ will this minimum deviation occur?

When white light passes through a glass prism,one gets a spectrum on the other side of the prism. In the emergent beam,the ray which deviates the least is:

$A$ 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......$^o$

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 $^{\circ}$)

The refractive index of a prism is $\sqrt{2}$ and the angle of the prism is $30^\circ$. One of the refracting surfaces of the prism is polished. $A$ monochromatic beam of light enters the prism and retraces its path. What is the angle of incidence at the first refracting surface of the prism in degrees (in $^\circ$)?