Question

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 deviation between them, also calculate the dispersive power.

Answer 1

As for small angle of prism `delta = (mu - 1)A`,
`delta_(B) = (1.659-1)xx 5^(@) = 3.295^(@) "and" delta_(R) = (1.641 -1)xx5^(@) = 3.205^(@)`
so `theta = delta_(B) - delta_(R)= 3.295^(@) = 0.090^(@)`