A microscope that uses two lenses to generate the magnified image of the object is called a compound microscope. The magnified image generated by one lens is further magnified by the second lens (Figure 14.3). Magnification of a compound microscope is the product of the magnification caused by the objective and ocular (eyepiece) lenses:
Figure 14.3 Ray optical diagram of a compound microscope
Resolution of microscope
Resolution of a microscope is defined as shown in figure 14.4.
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(14.1) |
Figure 14.4 Resolution of a microscope |
dmin = minimum distance between point objects that can be resolved λ = wavelength of the light source used n = refrective index of the medium between the objective lens and the specimen α = half of the objective angular aperture N. A. = numerical aperture = n sin α |
