1. Is it permissible for you to use the coarse focus knob with the oil immersion and high dry lenses?

Circle one: Yes or No

2. When observing the prepared bacterial smears at 1000X magnification, should your iris diaphragm be all the way open or           stopped down for minimal light? Circle the correct option and explain why.

3. Why should you start first with the scanning lens when viewing a slide?

4. When observing a slide, should the specimen be on the top surface or   bottom surface of the slide - circle your answer and explain your reason: 

5. As working distance increases, magnification _______________ (decreases or increases?)

6. When observing the wet mount of the pond water: a) What was the optimum magnification for seeing the protists? b) How should you adjust the light for optimal viewing?

7. What are the three general shapes you will see among the bacteria? Please illustrate and label.

8. You are viewing a sample under the 4x (scanning) objective lens. What is the total magnification of the sample as you see it:

9. You are viewing a sample under oil immersion objective, and your microscope gets bumped, causing the stage to move, and the sample to go out of focus. You should:

a) use the fine focus knob by turning it up to 10 full revolutions to bring your sample back into focus under the oil immersion objective

b) use the coarse focus knob to try to bring your sample back into focus under the oil immersion  objective

c) move the scanning (4x) lens into place, and bring your sample back into focus with this lens before moving sequentially back to the oil immersion lens