Question

The variation of refractive index of a crown glass thin prism with 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?

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

Answer 2

Since $D_m = (\mu - 1)A$ & on increasing the wavelength, $\mu$ decreases & hence $D_m$ decreases.