Which of the following can make a parallel beam of light when light from a point source is incident on it?
(A) Concave mirror as well as convex lens.
(B) Convex mirror as well as concave lens.
(C) Two plane mirrors placed at 90° to each others.
(D) Concave mirror as well as concave lens.
Answer -
Only converging lens and converging mirror can make a parallel beam of light incident on a point.
- Concave mirror is a converging mirror.
- Convex lenses converge to light rays, hence convex lenses are also called converging lenses .
So, the correct answer is (a) - Concave mirror as well as convex lens.