33)], when the
image is formed at infinity, is
m
m m
fL
fD
o
e
o
e
=
=







                                                                    (9 45)
Clearly, to achieve a large magnification of a small object (hence the
name microscope), the objective and eyepiece should have small focal
lengths In practice, it is difficult to make the focal length much smaller
than 1 cm Also large lenses are required to make L large