Question

The silvering on the back surface of a mirror can be done by:
(A) Silver
(B) Mercury
(C) both
(D) none

Answer 1

Hint
A plane mirror is a mirror with a flat (planar) reflective surface. For light rays striking a plane mirror, the angle of reflection equals the angle of incidence. The angle of the incidence is the angle between the incident ray and the surface normal (an imaginary line perpendicular to the surface).

Complete step by step answer
The most common mirrors consist of a plate of transparent glass, with a thin reflective layer on the back (the side opposite to the incident and reflected light) backed by a coating that protects that layer against abrasion, tarnishing, and corrosion.
A plane mirror is made from a few mm thick glass plate. One surface of a glass plate is polished to a high degree of smoothness. This forms the front part of the mirror. And the other (back) surface is silvered (i.e painted with silver, mercury or some other material).
Option (A) is correct.

Note
When photons (rays of light) coming from an object (your smiling face, for example) strike the smooth surface of a mirror, they bounce back at the same angle. Your eyes see these reflected photons as a mirror image.