Question

An object is 50 cm from a converging lens with a focal length of 40 cm . A real image is formed on the other side of the lens, 250 cm from the object. What is the magnification?a)1.25b) 5.5c) 3.0d) 4.0e) 0.25

Answer 1

Answer:

d) -4.0

Explanation:

The magnification of a lens is given by

$M=-\frac{q}{p}$

where

M is the magnification

q is the distance of the image from the lens

p is the distance of the object from the lens

In this problem, we have

p = 50 cm is the distance of the object from the lens

q = 250 cm - 50 cm is the distance of the image from the lens (because the image is 250 cm from the obejct

Also, q is positive since the image is real

So, the magnification is

$M=-\frac{200 cm}{50 cm}=-4.0$