Question

A ray of light falling at an angle of `50^@` is refracted through a prism and suffers minimum deviation. The angle of the prism is `60^@`. Find the angle of minimum deviation and refraction index of the material of the prism.

Answer 1

Here, `i_1 = 50^@, A = 60^@, delta_m = ? , mu = ?` In position of minimum deviation, `i_2 = i_1 = 50^@`
From `A + delta_m = i_1 + i_2 = 50 + 50 = 100^@`
`delta_m = 100^@ - A = 100 - 60^@ = 40^@`
`mu = (sin(A + delta_m)//2)/(sin A//2) = (sin(60^@ + 40^@)//2)/(sin 60^@//2) = (sin 50^@)/(sin 30^@) = (0.7660)/(0.5000) = 1.532`.