$A$ yellow light undergoes minimum deviation through a prism. If $i_1$ and $i_2$ are the angle of incidence and the angle of emergence respectively,then:

$A$ 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 $....\,nm.$

$A$ thin prism $P_1$ with an angle $6^{\circ}$ and made of glass of refractive index $1.54$ is combined with another prism $P_2$ made from glass of refractive index $1.72$ to produce dispersion without average deviation. The angle of prism $P_2$ is $........{}^{\circ}$

$A$ ray of light passes through an equilateral prism such that the angle of incidence $(i)$ is equal to the angle of emergence $(e)$. The angle of emergence is equal to $\left(\frac{3}{4}\right)$ of the angle of the prism. The angle of deviation is: (in $^{\circ}$)

The refractive index of a prism is measured using three lines of a mercury vapour lamp. If $\mu_1, \mu_2$ and $\mu_3$ are the measured refractive indices for these green,blue and yellow lines respectively,then

$A$ ray falls on a prism $ABC$ $(AB = BC)$ and travels as shown in the figure. The minimum refractive index of the prism material should be