How i can find the magnification of a lens?

[josue2503]

how i can find the magnification of a lens??

how i can find the magnification of a lens if i don't know it's focal length??

 

[Bright]

Just compare an original object and its (real or imaginary) image.

 

[josue2503]

what is the formula in finding the magnification?

what is the formula in finding the magnification if i don't know the focal length?

 

[Bright]

magnification M is

M = SI / SO

where

SI is size of image
SO is size of object

 

[josue2503]

if the lens is 4mm in diameter how i can find the magnification and focal length?

 

[Bright]

if the lens is 4mm in diameter how i can find the magnification and focal length?

magnification and focal length do NOT depend on diameter

 

[russ_watters]

if the lens is 4mm in diameter how i can find the magnification and focal length?

That doesn't tell you anything you need to know to find the focal length.