Question

A beam of light is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the following figure:

The box contains:

Options

• a glass prism

• a concave lens

• a convex lens

• a parallel-sided glass slab

Answer 1

A concave lens

Explanation:

The diagram shows that parallel light rays enter the box and spread outwards after emerging. A concave lens is a diverging lens that refracts parallel incident rays away from the principal axis, making them appear to diverge from a single focal point. The central ray passing through the optical centre travels straight without bending.