Consider an equilateral prism (refractive index $ \sqrt{2} $). $A$ ray of light is incident on its one surface at a certain angle $ i $. If the emergent ray is found to graze along the other surface, then the angle of refraction at the incident surface is close to . . . . . . . (in $^{\circ}$)

$A$ light ray incident normally on one face of an equilateral prism and emerges out grazingly at the other face. The refractive index of the prism is

The refractive index $(R.I.)$ of a prism is $\sqrt{\frac{7}{3}}$ and the angle of the prism is $60^{\circ}$. The limiting angle of incidence of a ray that will be transmitted through the prism is .....$^{\circ}$

Monochromatic light of wavelength $6000 Å$ is incident on a small-angled prism. If the angle of the prism is $6^{\circ}$ and the refractive indices of the material of the prism for violet and red lights are $1.52$ and $1.48$ respectively, then the angle of dispersion produced for this incident light is: (in $^{\circ}$)

$A$ 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 $^{\circ}$)?

Three thin prisms are combined as shown in the figure. The refractive indices of the crown glass for red,yellow,and violet rays are ${\mu _r}, {\mu _y}$ and ${\mu _v}$ respectively,and those for the flint glass are ${\mu _r}', {\mu _y}'$ and ${\mu _v}'$ respectively. If there is no net deviation in the yellow ray,then the ratio $A'/A$ will be: