For a symmetric (equilateral) prism,the prism formula can be written as

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:

$A$ thin prism having refracting angle $10^{\circ}$ is made of glass of refractive index $1.42$. This prism is combined with another thin prism of glass of refractive index $1.7$. This combination produces dispersion without deviation. The refracting angle of the second prism should be....$^{\circ}$

The cross-section of a prism is an equilateral triangle $ABC$ as shown in the figure. The minimum deviation is observed when the angle of incidence is equal to the prism angle. The time taken by light to travel from the midpoint $P$ of $BC$ to $A$ is $..... \times 10^{-10} \, s$. (Given: speed of light in vacuum $= 3 \times 10^8 \, m/s$ and $\cos 30^{\circ} = \frac{\sqrt{3}}{2}$)

The refractive index $(R.I.)$ of a prism is $\sqrt{\frac{7}{3}}$ and the angle of the prism is $60^{\circ}$. The limiting angle of incidence of a ray that will be transmitted through the prism is .....$^{\circ}$

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