Three attributes of microscopes are of particular importance, these are magnification, resolution and contrast. Magnification is a means of increasing the apparent size of the object. With a light microscope a specimen could quite easily be magnified by as much as 10.000x. Magnification of a microscope is calculated by multiplying the power of its eye pieces with its magnifying power of its objective.
Resolution or more correctly the minimum resolved distance, is the capacity to separate adjacent form or object. Contrast is important in distinguishing one part of cell from another. In light microscopes contrast is often obtained by fixing and staining the material.
A very high magnification can obtained by ordinary light microscope but their resolving power is limited. It is about 500 times better than unaided human eye, but this is still not enough for viewing some of the smaller sub-cellular structures. Electron beams have much shorter wavelength than visible light, electron microscopes are capable of resolving objects about 10,000 times better than unaided human eye. Therefore most of the sub-cellular structures are studied by electron microscope.
Resolution or more correctly the minimum resolved distance, is the capacity to separate adjacent form or object. Contrast is important in distinguishing one part of cell from another. In light microscopes contrast is often obtained by fixing and staining the material.
A very high magnification can obtained by ordinary light microscope but their resolving power is limited. It is about 500 times better than unaided human eye, but this is still not enough for viewing some of the smaller sub-cellular structures. Electron beams have much shorter wavelength than visible light, electron microscopes are capable of resolving objects about 10,000 times better than unaided human eye. Therefore most of the sub-cellular structures are studied by electron microscope.
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