# Resolution and Magnification -Biology

Only available on StudyMode
• Download(s) : 24
• Published : March 3, 2013

Text Preview
Notes for WK2 – 10 September
Lesson 1
* State the resolution and magnification that can be achieved by an electron microscope. * explain the need for staining samples for use in electron microscopy Lesson 2
* calculate linear magnification of an image such as photomicrograph or electron micrograph Key words
* Resolution= the ability to distinguish 2 separate points as distinct from each other. * Magnification= the number of times greater an image is than the actual object itself. Light microscopes have a low resolution, therefore if the magnification is above x1500then the image is not clear. If you use an electron microscope then u can achieve a higher resolution. How an electron microscope works…

Firstly electron microscope generates a lot of electrons. The beam of electrons has a wavelength of 0.004 nanometres .this allows the microscope to see the difference between an objects that are only 0.2 nanometres apart. Electron microscopes use magnets instead of actual lenses to focus the beam on the specimen u want to magnify. Electrons are not visible to the human eye so the image produced is projected onto a screen or photographic paper, this make a black and white image appear. The resolution of an electron microscope is 500 000 times greater than that of a human eye. In transmission electron microscopes (TEM), electrons are generated and pass through a thin sample. The electron passes through the thinner part of the sample easily and the denser part of the sample less easily. So this gives some contrast in the image that is going to be produced. The final image is produced in the viewing screen and is a 2- dimensional black and white image. The highest possible magnification with a TEM is x500 000. In transmission electron microscopes (TEM), electrons are generated and pass through a thin sample. The electron passes through the thinner part of the sample easily and the denser part of the sample less easily. So this gives some contrast in...