F.3 Bio.about microscope (20點)

[匿名]

2009-09-23 4:03 am

1. Why do we need to adjust the diaphragm ?

2. When using the high power objective for observation, we should
not focus with the coarse adjustment knob. Why ?

3.Which magnification is more suitable for counting for the number of
cells in a specimen, a low power or high power magnification ?

4. Suppose you are observing a freshwater flatworm with a microscope
and the flatworm moves to the right so that you cannot see it. In
which direction should you move the slide on the stage in order
to bring it back to the view ?

回答 (1)

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2009-09-24 1:56 am

✔ 最佳答案

1. It's because too much light will give a faint image but too little light will give a unclear image so we need to adjust to obtaina suitable amount of light for observations.

2. It is because the coarse adjustment knob will lead to a large degree of downward movement will will break the epecimen observing.

3. A low power. Because the view field is larger so we can count the number of cells.

4. To the left. It is because the image shown by the microscope is totally inverted.

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