Question

waht is linear magnification?

how is the unit of magnification related to the unit of power?

Answer 1

In simple terms, linear magnification basically tells how big or small an image is when compared to the size of the corresponding object. The size or dimensions are measured as either height or length.

It is thus the ratio of the image size to object size, in one dimension.

The linear magnification for a lens is written as

m = (v/u)

or

in terms of focal length m = - f / (u-f) [f - focal length and u - object distance]

now, as Power, P = 1/f

so,

m = -1/P(u- 1/P)

or

the magnification power relation will be

m = -1 / (u.P-1)

magnification is a unit less quantity while the unit of Power is Dioptre.