When a magnifying glass is put overtop an object, such as text, the text appears enlarged. There is an equation that can be used to determine any of the variables in the following:
M = hi
—-
ho
OR
M = -di
—–
do
…where M is the magnification. If the image is upright, M is positive; if the image is inverted, M is negative.
Sample Problem:
An object 7.5 cm height is placed in front of a converging lens. The real image appears inverted 21 cm on the other side of the lens. What is the magnification of the lens?
List: M = ?, hi = -21 cm, ho = 7.5 cm.
M = hi
ho
M = -21
7.5
M = -2.81
Therefore, the lens has a magnification of -2.81.
