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Microbiology: Laboratory Theory & Application, Brief 3rd Edition

Microbiology: Laboratory Theory & Application, Brief (3rd Edition)

Book Edition3rd Edition
Author(s)Leboffe, Pierce
ISBN9781617314773
PublisherMorton Publishing
SubjectBiology
Section 3-2: Calibration of the Ocular Micrometer
Data and Calculations
Section 3-3: Microscopic Examination of Eukaryotic Microbes
Section 3-5: Negative Stains
Observations and Interpretations
Section 3-6: Gram Stain
Observations and Interpretations
Section 3-7: Acid-Fast Stains
Observations and Interpretations
Section 3-8: Capsule Stain
Observations and Interpretations
Section 3-9: Endospore Stain
Observations and Interpretations
Section 3-10: Bacterial Motility: Wet Mount and Hanging Drop Preparations
Observations and Interpretations
Section 3-11: Bacterial Motility: Flagella
Observations and Interpretations
Section 3-12: Morphological Unknown

Chapter 3, Section 3-1, Data and Calculations, Exercise 1

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Here is a tip:

NA of a microscope is directly proportional to its resolution.

Explanation

  • Total magnification is calculated by multiplying the magnifying power of an objective lens and one ocular lens.
  • Low power setting microscope has a magnification of 100X and is used to examine large-sized specimens and a number of smaller specimens. The microscope is also aligned by using this setting. The numerical aperture of a lens signifies its ability to collect light.
  • High dry setting is used to obtain a clear, detailed, and sharp image of the specimen.
  • Oil immersion setting gives finer and detailed images of individual cells such as bacteria or red blood cells.
  • Scanning lens setting is used in order to get a general overview of the specimen on the slide.
  • Condenser lens is used to converge light from a divergent beam in order to illuminate the specimen being observed.

Verified Answer

  • In low power settings, objective lens and ocular lens both have 10X magnifications. Consequently, the total magnification will be 100X. The numerical aperture [NA] of the objective lens is 0.40 and the calibration of the ocular micrometer [μm/OU] is 25.
  • In a high dry setting, objective lens and ocular lens have 40X and 10X magnification, respectively. Accordingly, the total magnification will be 400X. The numerical aperture of the objective lens is 0.85 and the calibration of the ocular micrometer [μm/OU] is 19.
  • In an oil immersion setting, objective lens and ocular lens have 100X and 10X magnification, respectively. Consequently, the total magnification will be 1000X. The numerical aperture of the objective lens is 1.30 and the calibration of the ocular micrometer [μm/OU] is 2.5.
  • In scanning lens settings, objective lens and ocular lens have 4X and 10X magnification, respectively. Accordingly, the total magnification will be 40X. The numerical aperture of the objective lens is 0.4 and the calibration of the ocular micrometer [μm/OU] is 32.
  • The NA of a condenser lens is 1.25.
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