Question

The refractive indices of a prism for red, violet and yellow lights are `1.52, 1.62` and `1.59` resp. What is the dispersive power of the prism ? If mean deviation is `40^@`. What is angular dispersion produced by the prism ?

Answer 1

Correct Answer - `0.169 ; 6.76^@`
Here, `mu_r = 1.52, mu_v = 162 and mu_y = 1.59`
Dispersive power (omega)
=`(mu_v - mu_r)/(mu_y -1) = (1.62 - 1.52)/(1.59 - 1) = (0.10)/(0.59) = 0.169`
Angular dispersion : `delta_v - delta_r = omega xx delta`
=`0.169 xx 40^@ = 6.76^@`.