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2021-05-14

Why do we start focusing on the lowest power objective?

Why do we start focusing on the lowest power objective?

The depth of focus is greatest on the lowest power objective. Each time you switch to a higher power, the depth of focus is reduced. Therefore a smaller part of the specimen is in focus at higher power. Again, this makes it easier to find an object on low power, and then switch to higher power after it is in focus.

When should you use the low power objective lens on the microscope?

Low power objectives cover a wide field of view and they are useful for examining large specimens or surveying many smaller specimens. This objective is useful for aligning the microscope. The power for the low objective is 10X. Place one of the prepared slides onto the stage of your microscope.

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Which objective lens power should you always start with first?

When focusing on a slide, ALWAYS start with either the 4X or 10X objective. Once you have the object in focus, then switch to the next higher power objective.

Why is it important to start adjusting the objective at its lowest and moving upward when focusing?

4. Objective lenses Always start and end your microscope session by placing the lowest power objective lens in position. This will make it easier to prevent crashing the objective lens into the slide.

What structure should never be used with high power?

Microscope Short Answer Review

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Which two structures on the microscope will you use to focus on your specimen? Coarse Adjustment Knob & Fine Adjustment Knob
Why should you never use the coarse adjustment knob on high power? It will crack the slide.

What part is used to tilt the microscope for more a comfortable viewing?

Inclination Joint: Where the microscope arm connects to the microscope base, there may be a pin. If so, you can place one hand on the base and with the other hand grab the arm and rotate it back. It will tilt your microscope back for more comfortable viewing.

Is used in tilting the microscope?

Inclination Joint: A joint at which the arm is attached to the pillar of the microscope is called inclination joint. It is used for tilting the microscope.

When you increase magnification What happens to field of view?

The field of view is inversely proportional to the magnification of the objective lens. For example, if the diameter of your field of view is 1.78 millimeters under 10x magnification, a 40x objective will be one-fourth as wide, or about 0.45 millimeters.

How important is the coarse focus?

While looking at the objective lens and the stage from the side, turn the coarse focus knob so that the stage moves upward toward the objectives. Move it as far as it will go without touching the slide. Focus (coarse), The coarse focus knob is used to bring the specimen into approximate or near focus.

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When should you use the fine focus knob?

Fine Adjustment Knob – This knob is inside the coarse adjustment knob and is used to bring the specimen into sharp focus under low power and is used for all focusing when using high power lenses. Light Source – The light source in your microscope is a lamp that you turn on and off using a switch.

What is the purpose of the fine focus?

Fine Focus: A knob used to fine-tune the focus of a specimen in conjunction with the coarse focus. Field of View: The diameter of the circle of light seen through a microscope. Focus: The ability to achieve a clear image, typically achieved by moving either the eyepiece tubes or the stage.

What are the steps you should use to focus the image on the slide?

Terms in this set (6)

  1. Lower stage, use lowest objective lens (scanning), and place slide on stage.
  2. Use coarse adjustment knob to focus image.
  3. Use fine adjustment knob to “fine tune” the image.
  4. Center the image you want in the field of view.

What is the correct order of steps as you bring an object into focus under high power?

To focus your object at the next highest power look from the side of the stage and slowly rotate the objective lens (10X) into place and use the fine adjustment knob to bring your object into focus. To focus at the highest power, rotate the nosepiece to the objective lens (40X) while looking at it from the side.

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What is the proper procedure to focus object under high power?

Compound Microscopes Look at the objective lens (3) and the stage from the side and turn the focus knob (4) so the stage moves upward. Move it up as far as it will go without letting the objective touch the coverslip. Look through the eyepiece (1) and move the focus knob until the image comes into focus.

What are the steps in preparing and observing a wet mount?

Wet Mount:

  1. Place a drop of fluid in the center of the slide.
  2. Position sample on liquid, using tweezers.
  3. At an angle, place one side of the cover slip against the slide making contact with outer edge of the liquid drop.
  4. Lower the cover slowly, avoiding air bubbles.
  5. Remove excess water with the paper towel.

What is a limitation of the light microscope explain why this is a limitation?

The resolution of the light microscope cannot be small than the half of the wavelength of the visible light, which is 0.4-0.7 µm. When we can see green light (0.5 µm), the objects which are, at most, about 0.2 µm. Below this point, light microscope is not useful, as wavelength smaller than 400 nm is needed.

What are the limits of a light microscope?

The principal limitation of the light microscope is its resolving power. Using an objective of NA 1.4, and green light of wavelength 500 nm, the resolution limit is ∼0.2 μm. This value may be approximately halved, with some inconvenience, using ultraviolet radiation of shorter wavelengths.

What is a limitation of using electron microscopes to view specimens 4 points?

What is a limitation of using electron microscopes to view specimens? (4 points) You cannot view transparent specimens because of the microscope’s low resolution. Electron beams are dangerous and can only be used sparingly. You cannot view live specimens because the necessary preparation kills cells.