Three rays of light, namely red R , green ( G ) and blue ( B ) are incident on the face P Q of a right angled prism P Q R as shown in figure. The refractive indices of the material of the prism for red, green and blue wavelength are 1 . 27 , 1 . 42 and 1 . 49 respectively. The colour of the ray(s) emerging out of the face P R is :

Step-by-step solution

Assuming that the right angled prism is an isoceles prism, so the other angles will be 45 ° each. ⇒ Each incident ray will make an angle of 45 ° with the normal at face P R . ⇒ The wavelength corresponding to which the incidence angle is less than the critical angle, will pass through P R . ⇒ θ C = critical angle ⇒ θ C = sin - 1 1 μ ⇒ If θ C ≥ 45 ° the light ray will pass ⇒ θ C Red = sin - 1 1 1 . 27 = 51 . 94 ° Red will pass. &#