Three glass prisms $A, B$ and $C$ of the same refractive index are placed in contact with each other as shown in the figure,with no air gap between the prisms. $A$ monochromatic ray of light $OP$ passes through the prism assembly and emerges as $QR$. The conditions of minimum deviation are satisfied in which prisms?

Define incidence angle,emergence angle,and deviation angle in the context of a prism.

Angle of minimum deviation for a prism of refractive index $1.5$ is equal to the angle of prism. The angle of prism is $......^{\circ}$ $\left(\cos 41^{\circ}=0.75\right)$

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

$A$ ray of light is incident on the first face of an equilateral glass prism at an angle of incidence '$i$'. The emergent ray just grazes along the adjacent face. The refractive index of the prism is $\sqrt{2}$. The value of the angle of incidence at the first face is $(\sin 45^{\circ} = 1/\sqrt{2}, \sin 90^{\circ} = 1)$.

$A$ combination of two prisms,one of flint glass and another of crown glass,produces dispersion without deviation. The angle of the flint glass prism is $15^o$. The angle of the crown glass prism and the net angular dispersion will be respectively: (Given: for crown glass $\mu = 1.52, \omega = 0.02$; for flint glass $\mu = 1.65, \omega = 0.03$). (in $^o$)