Why does a plane mirror not produce magnification greater than unity?
**Concave mirror image formation** depends on object position: beyond C real inverted diminished between F and C, at C real inverted same size at C, between C and F real inverted magnified beyond C, at F image at infinity, within F virtual erect magnified behind mirror. A plane mirror reflects light such that the image distance equals the object distance, and the image is formed by direct reflection without convergence or divergence. This results in an image of the same size as the object, with a magnification of 1, as there’s no mechanism to alter the apparent size. Substituting values gives
Ref: NCERT > Physics Book > Ray Optics > Reflection by Spherical Mirrors and Mirror Formula