i. Ratio of linear size of image to that of the object, measured perpendicular to the principal axis, is defined as the lateral magnification.
∴ m = \(\frac{h_2}{h_1}=\frac{v}{u}\) (for spherical lenses)
m = \(-\frac{v}{u}\) (for spherical mirrors)
ii. For any position of the object, a convex mirror always forms virtual, erect and diminished image.
Thus, lateral magnification for convex lens is always m < 1.
iii. In the case of a concave mirror, it depends upon the position of the object.