At what angle of incidence should a ray of light be incident on a face of an equilateral prism if the angle of minimum deviation is $46^{\circ}$ (in $^{\circ}$)?

For an equilateral prism,it is observed that when a ray strikes grazingly at one face,it emerges grazingly at the other. Its refractive index will be

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:

$A$ ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence. If the angle of incidence is $45^o$,the angle of deviation will be.......$^o$.

$A$ ray of monochromatic light is incident on one refracting face of a prism of angle $75^o$. It passes through the prism and is incident on the other face at the critical angle. If the refractive index of the material of the prism is $\sqrt{2}$,the angle of incidence on the first face of the prism is.......$^o$.

$A$ ray of light is incident normally on one of the faces of a prism of angle $30^\circ$ and refractive index $\sqrt{2}$. The angle of deviation will be.....$^\circ$