A point source of light is placed in front of a plane (b) Only the reflected rays close to the normal meet at mirror.

Question

A point source of light is placed in front of a plane

(a) All the reflected rays meet at a point when produced
(b) Only the reflected rays close to the normal meet at mirror. a point when produced backward.
(c) Only the reflected rays making a small angle with backward. the mirror, meet at a point when produced backward.
(d) Light of different colours make different images.

Answer 1

(a) all the reflected rays meet at a point when produced backward

Explanation:

See the diagram below,

Take any ray PR which is reflected at Q and QR is the reflected ray. Since the angle of incidence is equal to the angle of reflection, 

∠PQN =∠RQN=∠OPQ =α RQ, when produced back, meets PO produced at P'. In right-angled triangles PQO and P'QO, ∠QPO =∠QP'O =α 

Thus both are equal in all respect. So, PO =P'O. 

For any other ray, it can be proved. Hence the option (a). P' becomes a virtual image of P.

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