Which of the following diagrams correctly shows the dispersion of white light by a prism?

$A$ parallel beam of light is incident from air at an angle $\alpha$ on the side $PQ$ of a right-angled triangular prism of refractive index $n=\sqrt{2}$. Light undergoes total internal reflection in the prism at the face $PR$ when $\alpha$ has a minimum value of $45^{\circ}$. The angle $\theta$ of the prism is (in $^{\circ}$)

$A$ thin prism $P_{1}$ with angle $4^{\circ}$ 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 for $P_{2}$ 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:

$A$ flint glass prism and a crown glass prism are to be combined in such a way that the deviation of the mean ray is zero. The refractive indices of flint and crown glasses for the mean ray are $1.620$ and $1.518$ respectively. If the refracting angle of the flint prism is $6.0^{\circ}$,what would be the refracting angle of the crown prism (in $^{\circ}$)?

For a symmetric (equilateral) prism,the prism formula can be written as