Question
Two monochromatic rays of light are incident normally on the face AB of an isosceles right-angled prism ABC. The refractive indices of the glass prism for the two rays ‘1’ and ‘2’ are respectively 1.35 and 1.45. Trace the path of these rays after entering through the prism. 
Solution
The propagation of ray diagrams is as shown below:
Both the rays will fall on the side AC with angle of incidence (i) equal to 45°.
Critical angle of ray 1 is greater than that of angle of incidence. Hence, it will emerge from the prism. Critical angle of ray 2 is less than that of i. Hence, it will be internally reflected.
