$A$ prism having refractive index $\sqrt{2}$ and refracting angle $30^{\circ}$ has one of the refracting surfaces silvered. The beam of light incident on the other refracting surface will retrace its path,if the angle of incidence is $\left[\sin \frac{\pi}{6}=0.5\right]$

$A$ prism of refractive index $n_{1}$ and another prism of refractive index $n_{2}$ are stuck together (as shown in the figure). $n_{1}$ and $n_{2}$ depend on $\lambda$, the wavelength of light, according to the relation:
${n}_{1}=1.2+\frac{10.8 \times 10^{-14}}{\lambda^{2}} \text{ and } {n}_{2}=1.45+\frac{1.8 \times 10^{-14}}{\lambda^{2}}$
The wavelength for which rays incident at any angle on the interface $BC$ pass through without bending at that interface will be $....\,nm.$

At what angle should a ray of light be incident on the face of a prism of refracting angle $60^{\circ}$ so that it just suffers total internal reflection at the other face? The refractive index of the material of the prism is $1.524$.

$A$ thin prism with angle $5^{\circ}$ and refractive index $1.72$ is combined with another prism of refractive index $1.9$ to produce dispersion without deviation. The angle of the second prism is . . . . . . . (in $^{\circ}$)

Three thin prisms are combined as shown in the figure. The refractive indices of the crown glass for red,yellow,and violet rays are ${\mu _r}, {\mu _y}$ and ${\mu _v}$ respectively,and those for the flint glass are ${\mu _r}', {\mu _y}'$ and ${\mu _v}'$ respectively. If there is no net deviation in the yellow ray,then the ratio $A'/A$ will be:

When light of wavelength $\lambda$ is incident on an equilateral prism kept in its minimum deviation position,it is found that the angle of deviation equals the angle of the prism itself. The refractive index of the material of the prism for the wavelength $\lambda$ is,then