Electron and Light microscopes The differences between electron and light microscopes 2.5 / 5 based on 3 ratings ? BiologyPractical applications of biologyASAQA Created by: Marianne BradleyCreated on: 26-09-10 15:02 Light microscope drawbacks Poor resolution because of the long wavelength of light. 1 of 4 Electron microscope benefits/drawbacks An electron beam has a short wavelength and therefore an electron microscope has a high resolving power. Electrons have a negative charge. This means that the beam can be focused by using an electronmagnet. Electrons are absorbed by molecules in the air. A near vacuum has to be created to make the microscope work efficiently. 2 of 4 TEM electron microscopes TEM: Transmission Electron Microscope A beam is passed through a thin section of the specimen. Some parts absorb electrons so this appears dark, whereas other parts allow electrons to pass through and this appears bright. The resolving power of a TEM is 0.1 nm which is very high. Specimens must be very thin, and it is difficult to built up a 3D image. 3 of 4 SEM electron microscopes SEM: Scanning Electron Microscope. Pass a beam back and forth through a specimen which can build up a 3D image. Has a lower resolving power than a TEM; 20nm but this is still 10x better than a light microscope. Specimens do not have to be as thin as in a TEM as the electrons do not penetrate. 4 of 4
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