Mirror formula shows the relation among distance of object, distance of image and focal length in case of spherical mirror. All distances are measured from pole of the mirror.
The distance of object is denoted by ‘u’
The distance of image is denoted by ‘v’
Focal length is denoted by f
By knowing any two, the third can be calculated using the mirror formula.
Magnification is the relative ratio of size of image formed by a spherical mirror to the size of object. Magnification is generally denoted by letter ‘m’.
Magnification m=Height of image h’/Height of object h
Relation among magnification, distance of object and distance of image:
Magnification m=Distance of image/Distance of object=−v/u
Where; m = magnification, h' = height of image, h = height of object, v = image distance and u = object distance.