$A$ beam of monochromatic light is incident at $i = 50^{\circ}$ on one face of an equilateral prism. If the angle of emergence is $e = 40^{\circ}$,then the angle of minimum deviation $\delta_m$ is:

$A$ ray of light is incident on a $60^{\circ}$ prism at the minimum deviation position. The angle of refraction at the first face (i.e.,incident face) of the prism is.......$^{\circ}$

$A$ ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence,and each of these angles is equal to $\left(\frac{3}{4}\right)^{th}$ of the angle of the prism. The angle of deviation is: (in $^{\circ}$)

Define the angle of minimum deviation.

Define incidence angle,emergence angle,and deviation angle in the context of a prism.

$A$ prism has a refracting angle '$A$'. The second refracting surface of the prism is silvered. $A$ light ray falling on the first refracting surface with an angle of incidence '$2A$' reaches the second surface and returns back through the same path due to reflection at the silvered surface. The refractive index of the material of the prism is: