Question

What is the minimum length of the mirror required to visualised the complete image of the body of a person of height H.

• A. $\frac{H}{2}$
• B. $\frac{H}{3}$
• C. $3H$
• D. $Cannotbefound$

Answer 1

The correct option is A $\frac{H}{2}$

The person must have to obtain a reflected ray one from his head and another reflected ray from the feet.

Geometrically, AC = AB + BC where
$AB=\frac{x}{2}$ and $BC=\frac{H-x}{2}$
$\Rightarrow AC=\frac{x}{2}+\frac{H-x}{2}$
$\Rightarrow AC=\frac{H}{2}$ i.e. length of the mirror is just half the height of person.