In the visible region, the dispersive powers and the mean angular deviations for crown and flint glass prisms are $\omega, \omega^{\prime}$ and $d, d^{\prime}$ respectively. The condition for obtaining dispersion without deviation, when the two prisms are combined, is:

The refractive index of a material of a prism of angles $45^o -45^o -90^o$ is $1.5$. The path of the ray of light incident normally on the hypotenuse side is shown in

Consider the following statements for the refraction of light through a prism,when the angle of deviation is minimum.
$(A)$ The refracted ray inside the prism becomes parallel to the base.
$(B)$ Larger angle prisms provide smaller angle of minimum deviation.
$(C)$ The angle of incidence and the angle of emergence become equal.
$(D)$ There are always two sets of angles of incidence for which the deviation will be the same,except at the minimum deviation setting.
$(E)$ The angle of refraction becomes double the prism angle.
Choose the correct answer from the options given below.

Two beams of red and violet colours are made to pass separately through a prism of $A=60^{\circ}$. In the minimum deviation position,the angle of refraction inside the prism will be

If the refractive angles of two prisms made of crown glass are $10^o$ and $20^o$ respectively,then the ratio of their angular dispersions will be

$A$ prism is made up of a material with a refractive index of $\sqrt{3}$. The angle of the prism is $A$. If the angle of minimum deviation is equal to the angle of the prism, then the value of $A$ is: (in $^{\circ}$)