$A$ 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 $^{\circ}$)

If one face of a prism of prism angle $30^{\circ}$ and refractive index $\mu = \sqrt{2}$ is silvered,the incident ray retraces its initial path. The angle of incidence is.......$^{\circ}$

When a white light passes through a hollow prism,then

$A$ certain prism is found to produce a minimum deviation of $38^{\circ}$. It produces a deviation of $44^{\circ}$ when the angle of incidence is either $42^{\circ}$ or $62^{\circ}$. What is the angle of incidence when it is undergoing minimum deviation (in $^{\circ}$)?

$A$ ray of light is incident at an angle of $60^o$ on one face of a prism of angle $30^o$. The emergent ray of light makes an angle of $30^o$ with the incident ray. The angle made by the emergent ray with the second face of the prism will be....$^o$

White light is split into a spectrum by a prism and it is seen on a screen. If we put another identical inverted prism behind it in contact,what will be seen on the screen?