Question

A plane mirror as placed at the bottom of a tank containing a liquid of refractive index, μ. P is a small object at a height h above the mirror. An observer, O vertically above P and outside the liquid P and find its image in a mirror. The apparent distance between these two will be

• A. $2\mu h$
• B. $\frac{2h}{\mu }$
• C. $\frac{2h}{\mu -1}$
• D. $h(1+\frac{1}{\mu })$

Answer 1

The correct option is B

$\frac{2h}{\mu }$

note that image formation by a mirror does not depend on the medium. as, $P$ is at a height $h$ above the mirror, image of if $d$ is depth of liquid in the tank, apparent depth of $P$,
$X_1=\frac{d-h}{\mu }$
$\therefore$ Apparent distance between $P$ and its image
$X_2-X_1=\frac{d+h}{\mu }-\frac{d-h}{\mu }=\frac{2h}{\mu }$