Question

Two plane mirrors, A and B, are placed parallel to each other at a distance of 40 cm. An object is placed 10 cm away from mirror A. What will be the distance between the first images of the object formed by the two mirrors?​

• A. 20 cm​
• B. 80 cm​
• C. 60 cm​
• D. 100 cm​

Answer 1

The correct option is B 80 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 from 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 from 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
$=20+60=80\text{cm}$