What is mirror formula used for:
In a spherical mirror, the distance of the object from its pole is called the object distance (u). the distance of the image from the pole of the mirror is called the image distance (v). You already know that the distance of the principal focus from the pole is called the focal length (f). The relation between these three quantities is given by the mirror formula. The mirror formula is
.This formula holds good for both concave and convex mirrors for all positions of the object.