The angle of a prism is $60^{\circ}$ and the angle of minimum deviation is $30^{\circ}$. The angle of incidence is ........$^{\circ}$.

The cross-section of a prism $(\mu = 1.5)$ is an equilateral triangle. $A$ ray of light is incident perpendicular on one of the faces. The angle of deviation of the ray is......$^o$

In the given figure,the face $AC$ of the equilateral prism is immersed in a liquid of refractive index $n$. For an incident angle of $60^{\circ}$ at the side $AC$,the refracted light beam just grazes along the face $AC$. The refractive index of the liquid is $n = \frac{\sqrt{x}}{4}$. The value of $x$ is (Given refractive index of glass $= 1.5$)

Which colour has more speed in a glass prism? Blue or yellow?

$A$ ray incident at ${15^o}$ on one refracting surface of a prism of angle ${60^o}$ suffers a deviation of ${55^o}$. What is the angle of emergence?

For a thin symmetric prism made of glass (refractive index $1.5$), the ratio of the angle of incidence to the angle of minimum deviation is . . . . . . .