Question

Two plane mirrors A and B are placed parallel to each other at a separation of $40\text{cm}$. An object is placed at a distance of $10\text{cm}$ from mirror A. What will be the distance between the images of the object formed by the mirrors?

• A. $60\text{cm}$
• B. $20\text{cm}$
• C. $100\text{cm}$
• D. $80\text{cm}$

Answer 1

The correct option is D $80\text{cm}$

The distance of object from mirror A $=10\text{cm}$
Distance of image from mirror A $=10\text{cm}$

Distance between object and image for mirror A $=10+10=20\text{cm}$

The distance of object from mirror B$=40-10=30\text{cm}$
Distance of image from mirror B $=30\text{cm}$

Distance between object and image for mirror B $=30+30=60\text{cm}$
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
$=20+60=80\text{cm}$