Two plane mirrors A and B are placed parallel to each other at a separation of $30\text{cm}$. An object is placed at a distance of $20\text{cm}$ from mirror A. What will be the distance between the images of the object formed by the mirrors?

The correct option is B $60\text{cm}$
The distance of object from mirror A $=20\text{cm}$
Distance of image from mirror A $=20\text{cm}$

Distance between object and image from mirror A$=20+20=40\text{cm}$

The distance of object from mirror B$=30-20=10\text{cm}$
Distance of image from mirror B $=10\text{cm}$

Distance between object and image from mirror B $=10+10=20\text{cm}$
Since the images are on either side of the object, the distance between the images will be given by:
Distance of image A from the object + distance of image B from the object
$=40+20=60\text{cm}$