Difference between Light and Electron Microscopy

this document provides the major differences between electron microscopy and light microscopy. This is one of the important chapters in Microbiology. Unit 1 Microbiology BT6202 notes. Anna university important 8 mark.

1. MICROBIOLOGY BT6202
LIGHT AND ELECTRON MICROSCOPY

Parameters Light Microscopy Electron
Microscopy
size Light microscopes are
smaller and lighter, so
are easier to move and
set-up.
Electron microscopes
are big and heavy, so are
hard to move and set-up.
cost Light microscopes are
less expensive than
electron microscopes.
Electron microscopes
are expensive.
radiation type Light microscopes use
light (approx
wavelength 400-700
nm)
Electron microscopes
use beams of electrons
(approx equivalent
wavelength 1 nm).
magnification Light microscopes have
much less magnification
than electron
microscopes
Electron microscopes
have much higher
magnification than light
microscopes
control of image
formation
Light microscopes via
glass lenses
In electron microscopes
beams of electrons can
be focused using
electromagnets due to
negative charge on
electrons.
resolution Light microscopes have
much lesser resolution
than electron
microscopes
Electron microscopes
have much higher
resolution than light
microscopes
color of images Light microscopes form Electron microscopes

2. images including the
range of wavelengths
(colors) provided by the
light source - but the
colors seen are often due
to stains rather than the
actual colors present in
nature)
produce grey-scale
(sometimes called "black
and white") images.
However, "false-color"
electron micrographs are
common - and can be
very beautiful
usage Living specimens can
also be viewed.
Living specimens cannot
be viewed using electron
microscopes because
electron microscopes
require there to be a
vacuum in the tube -
otherwise the electrons
would be absorbed by
air molecules.
image formation Light microscope
images can be viewed
directly
Electron microscopes
require use of a
fluorescent screen,
photographic plate or
electronic display
because electrons cannot
be observed directly by
the human eye.