Question

Trace the path of the ray (P) of light passing through the glass prism as shown in the figure. The prism is made of glass with critical angle i_c = 41°.

Answer 1

The ray of light P falls perpendicular on the surface of the prism. So, the angle of incidence, i = 0°. The ray will thus pass through the prism unaffected until it reaches the other end of the prism. Here, due to the geometry of the prism, the angle of second incidence will be equal to 45°. This is greater than the critical angle of the prism and thus the light will undergo total interval refection and will continue in the same manner.

The figure below shows the complete path of the light ray