Two plane mirrors are placed parallel to each other at a distance L apart. A point object O is placed between them, at a distance $\text{L/3}$ from one mirror. Both mirrors form multiple images. The distance between any two images cannot be

Two mirrors are parallel

The total Images is formed is infinite

Its plane mirror the object distance = Image distance

So$\text{L/3}$  for one mirror means$\text{2L/3}$  from the other mirror

So its forms image at $\text{2L/3}$

Distance

$\text{L/3}\left(\text{object}\right)\to \text{L/3}\left(\text{Image}\right)$

$\text{2L/3}\left(\text{object}\right)\to 2\text{L/3}\left(\text{Image}\right)$

So$\frac{\text{L}}{\text{3}}+\frac{\text{L}}{\text{3}}=\frac{\text{2L}}{\text{3}}$

$\frac{\text{2L}}{\text{3}}+\frac{\text{2L}}{\text{3}}=2\text{L}$

So the distance between any two Images cannot be$\text{3L/2}$