Question

.A person is standing at a distance of 20 cm from a plane mirror. The distance between the object and image is.​

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

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.

Answer 2

The distance of image from the plane mirror is same as the distance of object (person) from the plane mirror but the image is formed behind the mirror.
∴ v=u=3 m
Thus distance between image and the person d=u+v=3+3=6