The figures represent three cases of a ray passing through a prism of angle $A$. The case corresponding to minimum deviation is

One of the refractive surfaces of a prism of angle $30^{\circ}$ is silvered. $A$ ray of light incident at an angle of $60^{\circ}$ retraces its path. The refractive index of the material of the prism is:

The curve of angle of incidence versus angle of deviation shown has been plotted for a prism. The value of the refractive index of the prism used is:

$A$ prism is made up of material of refractive index $\sqrt{3}$. 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 $^{\circ}$)

The refractive index of glass for red light is $1.520$ and for blue light is $1.525$. Let $D_1$ and $D_2$ be the angles of deviation for red and blue light,respectively,in a prism of this glass. Then:

Yellow light is refracted through a prism producing minimum deviation. If $i_1$ and $i_2$ denote the angle of incidence and emergence for the prism,then ..........