Question

An object is placed in front of plane mirror, when the mirror is moved away from the object through a distance d, the image moves a distance 20 cm from the object then the distance d is
(A) 20 cm
(B) 40 cm
(C) 15 cm
(D) 10 cm

Answer 1

Answer: The total distance between the positions of the original and final image is 4 cm.

Explanation:

We know that,

For plane mirror,

The image distance = - The object distance

An object is placed 20 cm in front of a plane mirror then the image is formed at 20 cm behind the mirror.

If the mirror is moved 2 cm toward the object.

The distance between object and mirror = 20-2 = 18 cm

The distance between image and mirror = 20-2 = 18 cm

Therefore, the total distance between the positions of the original and final image is

d = distance of the original image - distance of the final image

Hence, The total distance between the positions of the original and final image is 4 cm.