A light ray is falling on a face of an equilateral glass prism as shown in the figure: Which one of the following diagrams correctly shows the complete path of the ray through the glass prism?

Step-by-step solution

When the light ray falls perpendicularly on the first face of the equilateral glass prism, its angle of incidence is 0^ . Thus, it enters the prism undeviated. In the triangle formed at the top vertex, the angle of the prism is 60^ , and the angle at the first face is 90^ . The angle between the ray inside the prism and the second face is 180^ - (90^ + 60^ ) = 30^ . The normal to the second face makes an angle of 90^ with the surface. The angle of incidence at the second face is 90^ - 30^ = 60^ . The critical angle