Write difference between Microscope and Electon Micro scope
Answers
Size: Light microscopes are smaller and lighter, so are easier to move and set-up.
Cost / Availability: Light microscopes are less expensive than electron microscopes.
Radiation Type: Light microscopes use light (approx wavelength 400-700 nm), electron microscopes use beams of electrons (approx equivalent wavelength 1 nm).
Control of image formation : Light via glass lenses, beams of electrons can be focused using electromagnets due to negative charge on electrons.
Resolution*: Electron microscopes have much higher resolution than light microscopes
Magnification*: Electron microscopes have much higher magnification than light microscopes
Colour Images: Light microscopes form images including the range of wavelengths (colours) provided by the light source - but remember that the colours seen are often due to stains rather than the actual colours present in nature). Electron microscopes produce greyscale (sometimes called "black and white") images. However, "false-colour" electron micrographs are common - and can be very beautiful!
Preparation of specimens : Generally involves harsher processes, e.g. using corrosive chemicals, for viewing via electron microscope than preparation of slides for viewing using a light microscope. Therefore more skill required - both to prepare specimens and to interpret EM images (due to "artefacts" in images, artefacts = features in images that are not present in the specimen but rather are due to the processes used to prepare the specimen and produce the image)
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.
Usage Limitations : 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.
