Question

Derive an expression for mirror formula using that show that for a plane mirror object distance is equal to the image distance.

Answer 1

We know that in a plane mirror the object is of the same size a that of object and we also know that
Magnification $=\frac{Heightofimage}{Heightofobject}=\frac{v}{u}$
Where V is the object distance and u is the image distance
And let magnification be M and we also know that height of image is same as that of object so cancelling out we get 1
Magnification $=1=\frac{V}{u}$
U = V
Therefore from above we can say that the object distance is same as that of image distance