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MICROBIOLOGY LAB EXA M 1
QUESTIONS & ANSWERS( SCORED A)
Question : Microscope- The Condenser
Correct answer: focuses the light ging into the objective
lens
Question : Microscope- The Iris Diaphragm
Correct answer: adjusts the amount of light going into the
objective lens
Question : Microscope- Nosepiece
Correct answer: holds the objective lenses and rotates to
change from one objective to another
Question : Microscope- Coarse Objective Knob
Correct answer: moves the stage larger distances to help
get the object in focus
Question : Microscope- Fine Adjustment Knob
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Correct answer: moves the stage smaler increments to
help get the object in better focus
Question : Microscope- Objective Lens
Correct answer: magnifies the object. It is located near the
object.
Question : Microscope- Occular Lens
Correct answer: magnifies the image of the object from
the objective lens. It is located near the eye.
Question : Steps in using the microscope
Correct answer: 1) scanner power in place
2) place slide of specimen stage in place with stage clips 3) Using the course adjustment knob, raise the stage all the way up and then down slowly until you can see image of specimen 4) Readjust with fine adjustment knob
Question : Describe the purpose of the oil immersion lens
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Correct answer: Used when oil is added to the slide. Oil
must touch the object and objective lens to that the light does not refract futher
Question : Parfocal
Correct answer: Parfocal microscopes are able to move
from one objective to the next and still be in focus due to the length of the objective lenses
Question : Resolution
Correct answer: The ability to distinguish between two
objects that are very close together.
Question : What is resolving power?
Correct answer: The measurement of resolution
Question : What are two ways to increase resolving
power?
Correct answer: 1. By decreasing the wavelength of light
(using a blue filter) 2. Increasing the numerical aperature
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Question : What units are used to express resolving
power?
Correct answer: nm or nanometers
Question : What is better, smaller or larger resolving
power?
Correct answer: Smaller is better
Light microscopes have a 200nm resolving power Electron microscopes have a .2nm resolving power
Question : What is chromatic aberration?
Correct answer: The effect when many colors are seen
toward the edge of the microscope field of vision (like a prisim)
Question : How are microscopes corrected for chromatic
aberration?
Correct answer: With a special achromatic lens (corrected
for red and blue light) or by using a blue filter. The lab