White light is passed through a prism of angle `5^(@)`. If the refractive indices for red and blue colours are `1.641 "and" 1.659` respectively , calculate the angle of dispersion between them.

Explanation

As for small angle of prism ` delta = ( mu -1) A ,`
` delta _h =( 1.659 -1) xx 5^0 = 3.2295 ^0 and `
` delta_r = (1.641 -1) xx 5^@ = 3.205^@ ` so
` theta = delta _b - delta _r = 3.2 295 ^0 - 3.205^@ = 0.090 ^@`