Chapter-9|Ray Optics and Optical Instrument|NCERT 12th Physics:
Linear Magnification Produced by a Lens(m):
Linear magnification of a lens is defined as the ratio of the height of the image formed by the lens and height of the object.
Here we will use hᵢ and h₀ with sign. Height above principal axis is positive and below negative.
Proof of m= v/u :-
4. |m|<1, means. hᵢ<h₀
→diminished image.