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

$A$ monochromatic ray of light is incident normally on a thin prism of refracting angle $A$. The ray is deviated through an angle $(1.15)^{\circ}$ in passing through the prism. The ray reflected internally from the second face emerges from the first face making an angle of $(6.3)^{\circ}$ with the incident ray. The refractive index of the prism is

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

The angle of a prism is $A$. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence $2A$ on the first surface return back through the same path after suffering reflection at the silvered surface. The refractive index $\mu$ of the prism is:

$A$ ray of light is incident normally on the first refracting face of a prism of refracting angle $A$. The ray of light comes out at grazing emergence. If one half of the prism (shaded portion) is knocked off,the same ray will:

The angle of minimum deviation for an incident light ray on an equilateral prism is equal to its refracting angle. The refractive index of its material is