Question

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

Options

• Concave mirror as well as convex lens

• Convex mirror as well as concave lens

• Two plane mirrors placed at 90° to each other

• Concave mirror as well as concave lens

Answer 1

Concave mirror as well as convex lens

Explanation - 

When the point source is kept at the focus of the concave mirror and convex lens, the light rays after reflection and refraction respectively, will become parallel to the principal axis.