Question

What is the minimum length of a plane mirror required for a person to see his or her full image?

Answer 1

The minimum length of the mirror should be half the height of the man, this is because, at half the length of the height, the angle of incidence equals the angle of reflection, in the case of reflection.

The minimum length of a plane mirror to see the full height of one’s body is,

$L_{min}=\frac{H}{2}$

where $H$ is the height of the person.