When white light passes through a glass prism,one gets a spectrum on the other side of the prism. In the emergent beam,the ray which deviates the least is:

$A$ thin prism of angle $15^o$ made of glass of refractive index $\mu_1 = 1.5$ is combined with another prism of glass of refractive index $\mu_2 = 1.75$. The combination of the prisms produces dispersion without deviation. The angle of the second prism should be ......$^o$

$A$ ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence,and each of these angles is equal to $(3/4)$ of the angle of the prism. The angle of deviation is .......$^o$.

The variation of the refractive index of a crown glass thin prism with the wavelength of the incident light is shown. Which of the following graphs is the correct one,if $D_m$ is the angle of minimum deviation?

One side of an equilateral prism is painted by a transparent material of refractive index $n_2$. The refractive index of the prism is $1.6$. The minimum value of $n_2$ required for total internal reflection from the painted face is . . . . . . .

$A$ small-angled prism is made of a material of refractive index $\frac{3}{2}$. The ratio of the angles of minimum deviation when the prism is placed in air and in water of refractive index $\frac{4}{3}$ is: