Question

(b) three light rays red (R), green (G) and blue(B) are incident on the right angled prism abc at face ab. The refractive indices of the material of the prism for red,green and blue wavelength are respectively 1.39,1.44 and 1.47. Trace the paths of these rays reasoning out the difference in their behavior.

Answer 1

1. when the three light rays say red, green and blue are made to incident on face ab of prism, then no refraction occurs at face ab. Out of three rays red ray will emerge out where as blue and green undergoes total internal reflection.
2. The Reason is as red colour has maximum wavelength, hence n for red is minimum.And critical angle for red is maximum hence except red colour , blue and green will incident at face AC more than critical angle.