The distance between the object from the pole of a spherical mirror is called object distance and the distance between the image formed from the pole of the mirror is called the image distance. The focal length is the distance between the principal focus and the pole of the spherical mirror.The mirror formula gives us the relation between the object distance, image distance, and the focal length which is given by the formula:\\[\\frac{1}{v}+\\frac{1}{u}=\\frac{1}{f}\\]Here, v denotes the image distance, u denotes the object distance and f denotes the focal length of the spherical mirror.