Question

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

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Image formation by a mirror (either plane or spherical) does not depend on the medium.
The image of P will be formed at a distance h below the mirror. If d = depth of liquid in the tank.

Apparent depth of $x_1=\frac{x}{\mu }$ where $x$ is real depth and $\mu$ is refractive index

Apparent depth of $P=x_1=\frac{d-h}{\mu }$

Apparent depth of the image of $P=x_2=\frac{d+h}{\mu }$

$\therefore$ Apparent distance between P and it's image $=x_2-x_1=\frac{2h}{\mu }$