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

$A$ thin prism of angle $6^{\circ}$ made of glass of refractive index $1.5$ is combined with another prism made of glass of refractive index $1.75$ to produce dispersion without deviation. Then the angle of the second prism is ...... (in $^{\circ}$)

$A$ ray of light is incident on an equilateral glass prism placed on a horizontal table. For minimum deviation,which of the following is true?

Assertion: There exist two angles of incidence for the same magnitude of deviation (except for minimum deviation) by a prism kept in air.
Reason: In a prism kept in air,a ray is incident on the first surface and emerges out of the second surface. If another ray is incident on the second surface along the path of the previous emergent ray,then this ray emerges out of the first surface along the path of the previous incident ray. This principle is called the principle of reversibility of light.

$A$ ray of light is incident normally on the diagonal face of a right-angled prism as shown in the figure. If $\theta = 37^o$ and the refractive index of the prism is $\mu = 5/3$,then the angle of deviation is......$^o$ $(\sin37^o = 3/5)$

$A$ parallel beam of monochromatic light is incident at one surface of an equilateral prism. The angle of incidence is $55^o$ and the angle of emergence is $46^o$. The angle of minimum deviation will be: