The refractive index of the material of a small-angled prism is $1.6$. If the angle of minimum deviation is $4.2^{\circ}$, the angle of the prism is: (in $^{\circ}$)

$A$ light ray is incident at an angle of $60^o$ on a prism of angle $45^o$. When the light ray emerges from the other surface at $90^o$ to the surface,the refractive index of the material of the prism $\mu$ and the angle of deviation $\delta$ are given by:

$A$ given ray of light suffers minimum deviation in an equilateral prism $P$. Additional prisms $Q$ and $R$ of identical shape and material are now added to $P$ as shown in the figure. The ray will suffer

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 $^{\circ}$)

$A$ 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 . . . . . . .

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