Question

A camera lens used for taking close-up photographs has a focal length of 25 mm. The farthest it can be placed from the film is 44 mm. What is the magnification of this closest object?

Answer 1

Answer:-

$m=-\frac{d_i}{d_o}\\ d_i=44 \ mm$ ​(distance between the image and the lens

$d_o=$ ​? (distance between the object and the lens

f=25mm ( focal length)

$\frac{1}{d_0}=\frac{1}{f}-\frac{1}{d_i}$

$\frac{1}{d_0}=\frac{1}{25}-\frac{1}{44}$

$d_o=57.894 \ mm$

magnification of this closest object

$m=-\frac{d_i}{d_o}\\$

$m=-\frac{44}{57.894}\\$ ​$=\boxed{0.760}$