introduction to microscopy. objectives learn to use a compound microscope correctly. diagram the...
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Introduction to Microscopy
Objectives
• Learn to use a compound microscope correctly.
• Diagram the path of light through a compound microscope.
• Name major parts of a compound microscope.• Identify three basic morphologies of bacteria.
Size in Microbial World
Magnification
•Refraction (bending) of light as it passes through the lens produces magnified image•Two sets of lens contribute to total magnification •Four objective lenses: 4x (scanning), 10x (low power), 40-45x (high power), 100x (oil immersion).•Ocular lens: 10x
Resolution Wavelength of light usedResolving Power = 2 x numerical aperture
Qualities of a Good Image
Brightness - related to NA. Focus - related to Focal Length.
Resolution - related to NA & λ. Contrast - related to illumination (can be improved)
Focusing and Iris Diaphragm
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