Question

Two plane mirrors A and B are placed parallel to each other at a separation of
40 cm. Alex is standing at a distance of 10 cm from mirror A. What will be the distance between the first set of images of Alex formed by the mirrors?

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

Answer 1

The correct option is C 80 cm


Given,
The distance of the object from mirror A = 10 cm
Since object distance from the mirror = image distance from the mirror,

Distance of image ($I_1$) from mirror A = 10 cm
Distance between object and image ($I_1$) = 10 + 10 = 20 cm

The distance of object from mirror B = 40 - 10 = 30 cm
Distance of image ($I_2$) from mirror B = 30 cm
Distance between object and image ($I_2$) = 30 + 30 = 60 cm

Since the images are on either side of the object, the distance between the images will be given by:
Distance of image ($I_1$) from the object + Distance of image ($I_2$) from the object
⇒ 20 + 60 = 80 cm
Thus, the distance between the first set of images of Alex formed by the mirrors is 80 cm.