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| What is magnification? How is it calculated? |
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Definition
| Factor by which an image is magnified. It is calculated by multiplying the power of the ocular lens (ALWAYS 10) by the power of the objective lens. |
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| What is the highest magnification for a compound light microscope? |
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| What is resolving power? How is it calculated? |
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Definition
| The ability to distinguish two objects as separate. Calculated as the distance between 2 objects (ex: 10 nanometers). |
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| What is the max resolving power for a compound microscope? |
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| What is the contrast? How is it increased? |
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Definition
| The apparent difference of images against a background. Dyes. |
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| How can one improve resolution? |
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Definition
| 1.) Iris diaphragm - alter light intensity. Higher levels of magnification require higher levels of light intensity. Closing the iris can improve resolution by eliminating light diffusion but it is still limited to 1000 x. |
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| What are 3 microscopes used that have better resolution than compound light microscopes? |
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Definition
1.) Phase contrast scope: transforms phase shifts caused by light passing through 2 objects into differences in light intensity. Produces a higher contrast image but is still limited to 1000 x. NORMANSKI PROCESS.
2.)Transmission Electron: Transforms differences in the stream of electrons passing through different objects into differences in light intensity. Requires staining of the specimen with heavy metal ions. Magnifications up to 106 X (one million) are possible.
3.) Scanning electron microscope: electron beams directed upon gold or platinum plated surfaces cause a scattering of electrons. The more direct the scattering into a detector, the higher the intensity, giving surfaces a shiny metallic, 3-dimensional appearance. |
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| 1um = ________ nm = __________ A |
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