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15 Cards in this Set
- Front
- Back
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Be able to list and diagram the parts of a microscope (16).
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-ocular lens -ocular eyepiece -diopter ring -revolving nosepiece -eyepiece sleeve -objectives -mechanical stage with travel knobs -coarse and fine adjustment knobs -condensor -rheostat -arm -base -stage
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What are the 6 working regions of a microscope?
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-ocular
-objectives (red, yellow/green, blue, white) -specimen stage -substage condenser and light source -focus control -base |
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How can you control intensity and quality of light reaching the objective?
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-rheostat (on-off switch)
-iris diaphragm (open has lower contrast, better resolve) -condenser |
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When is the greatest intesity of light on the specimen in terms of the condenser?
Where should it be positioned for stained and wet mounts? |
-when it's at its highest position
*stained smears: 102mm below slide *wet mounts: lowest level |
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Who made the first microscope?
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-Anton Van Leeuwenhoek
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What is the microscope we will mostly be using in this lab?
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-the compound brightfield microscope
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What are the three lens' used in todays compound microscope?
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-condenser
-objective lens -ocular lens |
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Why does the 100X need oil?
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-It can't take in enough light to be useful
-oil has similar refractive index so light isn't scattered as much and results in greater resolution |
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What are the markings found on each objective?
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-E=type of objective
-100=objective magnification -1.25 oil=numerical aperture -160/0.17= mechanical tube length/cover glass thickness correction |
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How do you find the resolution for a microscope?
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wavelength light/(NA obj lens + NA con lens)
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What is the calculation for finding NA?
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NA= n sin(theta)
n= refractive index of medium between specimen and lens sin(theta)= sin function of half the total angle of the cone of light trapped by the lens |
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What are the two fixed faxtors when calculating the resolution of a lens?
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-wavelength of visible light
-angle of incident light rays trapped by objective can not be greater than 60 degrees (sin < 0.866) |
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What does parfocal mean?
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-When switching from low to higher power, image should be nearly focused
*use only fine focus knobs! |
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What should you check before putting the scope back in its cabinet?
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-4x objective over hole
-clean all lenses -using kimwipe, clean any oil or debris off stage -fold cord and put under stage on base -center slide older -cover microscope |
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Be able to describe how to observe a sample in the microscope.
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pg's 9 and 10 in Appendix A
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