Question

A ray of light becomes parallel to the principal axis after reflection from a concave mirror. Which of the following can be concluded regarding the incident ray?

• A. It must pass through the centre of curvature.
• B. It must pass through the focus.
• C. It must be parallel to the principal axis.
• D. It must incident on the pole.

Answer 1

The correct option is B It must pass through the focus.

A ray of light passing through the focus of a concave mirror would become parallel to the principal axis after reflection.