Question

A light ray incident at an angle of incidence i passes an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges at an angle of emergence 'e'. Then

• A. $\angle i=\angle e$
• B. $\angle e=\frac{\angle i}{2}$
• C. $\angle e=2\angle i$
• D. $\angle e=2\angle i-A$

Answer 1

The correct option is A $\angle i=\angle e$

In this case, the refracted ray inside the prism is parallel to the base. After emerging the ray would make an angle with the normal to the surface equal to that made by the original incident ray at its refracting surface. This is because the prism is equilateral and therefore the ray will make similar angles with both the faces.