The Importance Of A Light Microscope

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A light microscope (LM) is an instrument that uses visible light and magnifying lenses to verify small objects that are not visible to the naked eyes or in finer detail than the naked eye allows. A light microscope uses two or more lenses to magnify the specimen and it have two sets of lenses which is stage and ocular (Bregman, 1983). Specimens are magnified by the objective lens which is magnified 100 times. The specimen is illuminated by visible light from the light source (the illuminator) that is passed through a condenser, which directs the light rays through the specimen. Resolution (resolving power) is the ability of a microscope to differentiate between two points. The resolution became better if the wavelength of the illumination is shorter. The white light used in a light microscope limits resolving power to about 0.2μm. The lenses which are closest to the specimen are the objective lenses. For the highest magnification, it is necessary to use oil immersion. Immersion oil has the same refractive index as glass that is the relative velocity of light passing through it is the same. Without…show more content…
A thin film of a microbial suspension, which is called a smear, is spread on the surface of a slide. Flaming the air-dried smear coagulates the microbial proteins and fixes the microorganisms to the slide so they do not wash off. The smear then can be stained. Basic dyes have a colored ion that is positive. It is helping them adhere to bacteria, which are slightly negative. Crystal violet, methylene blue, and safranin are the examples of basic dyes. Acidic dyes are having a negative color ion, are more attracted to the background than to the negatively charged bacteria. Thus, a field of colorless bacteria is presented against a stained background. This is an example of negative staining. An example of an acidic dye is

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