Beams of light are incident through the holes A and B and emerge out of box through the holes C and D respectively as shown in Figure. Which of the following could be inside the box ?

Options

A. A rectangular glass slab
B. A convex lens
C. A concave lens
D. A prism

Answer

A

Explanation

Here, the emergent rays are parallel to the direction of the incident ray. Therefore, a rectangular glass slab could be inside toe box as the extent of bending of light ray at the opposite parallel faces AB (air-glass interface) and CD (glass-air interface) of the rectangular glass slab are equal and opposite. This is why the ray emerges parallel to the incident ray.