Questions and Answers
What are the 4 types of Light Microscopes?
What is a Brightfield Microscope?
A microscope that allows light rays to pass through a slide/specimen and then through various lenses to the eye.
Microscopes are very expensive and must be handled with care.
True
How should microscopes be transported?
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What are the microscope parts and their functions?
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What are the three lens systems in a microscope?
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What does total magnification equal?
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What are the two focusing knobs?
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Describe the ocular adjustment.
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Define resolution.
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Resolution is a function of what three things?
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What is the optimum resolution of the best microscope with the oil immersion lens?
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How to increase resolution?
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What is numerical aperture (NA)?
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What is the limit of resolution?
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What does parfocalization mean?
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Oil has the same refractive index as what?
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Study Notes
Light Microscopes
- Four types of light microscopes: Bright-field, Dark-field, Phase contrast, and Fluorescence.
- Bright-field microscope: Allows light transmission through specimens to magnify and visualize objects.
Microscope Care and Transport
- Microscopes are costly and require careful handling.
- Transport using one hand on the arm and the other under the base for stability.
Microscope Parts and Functions
- Arm: Supports all microscope components.
- Base: Provides stability as the bottom part.
- Stage: Platform for holding slides.
- Mechanical stage: Clamps slides and facilitates movement.
- Light source: Illumination component located in the base.
- Voltage control: Adjusts light intensity; lower settings prolong lamp life.
- Lens system: Comprises ocular, objective, and condenser lenses.
- Focusing knobs: Includes coarse and fine adjustment knobs.
- Ocular adjustment: Aligns eyepieces to create a single image.
Lens Systems
- Ocular lens: Eye piece with 10X magnification and multiple lenses.
- Objective lens: Four options on the nosepiece—Scanning (4X), Low power (10X), High Dry (40X), Oil immersion (100X).
- Condenser lens: Located beneath the stage, it collects and directs light for uniform illumination.
Magnification and Resolution
- Total magnification calculated as ocular magnification times objective magnification.
- Resolution defines the clarity to distinguish between two separate points.
Factors Affecting Resolution
- Influenced by numerical aperture, wavelength of light, and condenser design.
- Best resolution attainable with oil immersion lens is 0.2 micrometers.
Improving Resolution
- Utilize blue or green filters to reduce wavelength and enhance resolution.
- Elevate condenser to maximize light entry.
- Open diaphragm for increased numerical aperture.
- Apply immersion oil between slide and 100X objective for optimal clarity.
Numerical Aperture and Limits of Resolution
- Numerical aperture (NA) measures lens light-capturing ability, improves with oil usage and higher objectives.
- Limit of resolution defined by the formula: D = Wavelength / (NA condenser + NA of objective lens).
Parfocalization
- Refers to the ability of the microscope to maintain focus when switching between objective lenses.
Refractive Index of Oil
- Oil matches the refractive index of glass, preventing light diffraction and loss, ensuring sharper image quality.
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Description
Test your knowledge on different types of light microscopes with this flashcard quiz. Learn about brightfield, dark-field, phase contrast, and fluorescence microscopes. Perfect for students in biology or microscopy courses!