Question

White light is passed through a prism having angle 5°. If the refractive indices for red color and blur color are 1.641 and 1.659 respectively. Find the angle between them.

(a) 3.295°

(b) 4°

(c) 0.090°

(d) 0.65°

Answer 1

The correct option is (c) 0.090°

To elaborate: For small angle of prism, deviation is given by;

α=(µ-1)*A

for blue color:- α1 = (1.659-1)*5° = 3.295° and

for red color:- α2 = (1.641-1)*5° = 3.205° so

therefore, Ө = α1 – α2 = 3.295°-3.205° = 0.090°.