Given, Initially, the distance of object A in front of plane mirror M is AM = 60 cm, therefore image B is at a distance MB = 60 cm from mirror M behind it. Distance between the object A and it’s image B = 60 + 60 = 120 cm
On shifting the mirror by 25 cm away from the object, the new distance of object A from the mirror M’ becomes AM’ = 60 + 25 = 85 cm . The new image B’ is now at a distance M’B’ = 85 cm behind the mirror M’.
Hence, the current distance of the image from the object is 85 cm + 85 cm = 170 cm
Let the reference point be the position of the object,
So, the new distance of the image from the object – the distance of the image from the object initially = distance between the two positions of the image
Hence,
170 cm – 120 cm = 50 cm
Therefore,
the image shifts 50 cm from its previous position.
