You have learnt in the text how Huygens’ principle leads to the laws of reflection and refraction. Use the same principle to deduce directly that a point object placed in front of a plane mirror produces a virtual image whose distance from the mirror is equal to the object distance from the mirror.
You have learnt in the text how Huygens’ principle leads to the laws of reflection and refraction. Use the same principle to deduce directly that a point object placed in front of a plane mirror produces a virtual image whose distance from the mirror is equal to the object distance from the mirror.

Answer –

Consider an item O placed at a distance r in front of the plane mirror MO’. The object is designated as point O, and a circle is drawn around it, just touching the plane mirror at point O’.

The wavefront of incident light, according to Huygens’ Principle, is XY. If the mirror was absent, a wavefront X’Y’ (as XY) would form behind O’ at a distance of r. For the plane mirror, X’Y’ can be thought of as a virtual reflected ray. As a result, putting a point object in front of a plane mirror produces a virtual picture with the same distance from the mirror as the object distance (r).