If an incident ray is reflected back along the same path in a concave mirror, then through which point does thatray pass?

Correct option is D

The correct answer is (d) Centre of curvature C.
· When a ray of light is incident on a concave mirror and is reflected back along the same path, it must pass through the centre of curvature (C) of the mirror.
· This happens because, at the centre of curvature, the incident ray strikes the mirror along the normal to the surface, meaning the angle of incidence is zero. According to the law of reflection, when the angle of incidence is zero, the ray is reflected back along the same path.
· The centre of curvature is the point on the principal axis where all rays parallel to the axis converge after reflection.
Additional Information:
· Focus F: Rays passing through the focus become parallel after reflection, but the ray would not return along the same path.
· Any point between focus F and centre of curvature C: This would result in the ray being reflected at an angle, not along the same path.
· Pole P: The point at the center of the mirror's surface, but not where reflection back along the same path would occur unless the incident ray is perpendicular.