An object is 80cm in front of plane mirror’M’. If the object is moved 0.20 m away from the mirror, how does the image shift from its previous image?

We know that in a plane mirror object distance = image distance

initially object distance = 80 cm = 0.8 m
So image is formed at 0.8 m behind the mirror.

then if object is moved 0.20 away total object distance becomes = (0.8+0.20 ) m = 1 m

Then the image will be at 1 m behind the mirror too.

Change in position = final position - initial position = 1 m - 0.8m = 0.2 m away from mirror.

Regards