Which of the following can make a parallel beam of light from a point source is incident on it ?

Options

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 other
D. Concave mirror as well as concave lens

Answer

A

Explanation

When a point source of light is placed at the focus of concave mirror then all light rays after reflection through mirror will become parallel to the principal axis. When this point source of light is placed at the focus of convex lens then after refraction by light rays convex lens will become parallel to the principal axis.