i) Explain why a ray of light passing through the centre of curvature of a concave mirror gets reflected along the same path.

ii) Draw the given diagram in your answer-book and complete it for the path of a ray of light beyond the lens.

i) The reflecting surface of a spherical mirror forms a part of a sphere. This sphere has a centre. This point is called the centre of curvature of the spherical mirror.

A ray is passing through the centre of curvature of a concave mirror after reflection is reflected along the same path. The light rays come back along the same path because the incident rays fall on the mirror along the normal to the reflecting surface.

Note:

ii) A ray of light from the object, parallel to the principal axis, after refraction from a convex lens, passes through the principal focus on the other side of the lens.