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

Correct option is D

The correct answer is (d) Centre of curvature C.
· In a concave mirror, if an incident ray is reflected back along the same path, it must have passed through the centre of curvature (C).
· This happens because the centre of curvature lies on the principal axis, and the incident ray strikes the mirror perpendicularly at that point, ensuring that it retraces its path.
Explanation of Other Options:
· Focus F : Rays passing through the focus are reflected parallel to the principal axis, not back along the same path.
· Any point between F and C : Rays passing through such points do not retrace their path.
· Pole P : Rays striking the pole follow the laws of reflection, but they do not retrace their path unless the incident angle is specific.
Key Concept:
· The centre of curvature is the center of the sphere of which the concave mirror is a part. A ray passing through it strikes the mirror at 90°, ensuring reflection along the same path.