Chapter 3 – The Invisible World: Microscopy

1. A compound microscope has _____ set(s) of lenses.

A. one B. two C. three D. four

B. two 

2. When looking through the __________ microscope, the specimen appears as a dark object against a light background.

A. fluorescence B. dark field C. bright field D. electron

C. bright field

3. Which microscope provides three-dimensional images?

A. Scanning electron microscope (SEM) C. dark field microscope

B. Nomarski microscope D. fluorescence microscope

A. Scanning electron microscope (SEM)

4. What is the approximate magnification of the low-power objective?

A. 4X B. 10X C. 40X D. 100X

B. 10X

5. The microscope platform upon which specimen slides are placed is called the ________.

A. shelf B. arm C. base D. stage

D. stage

6. Which of the following microscope objectives is used for final and fine focusing?

A. scanning B. low-power C. high-power D. oil-immersion

C. high-power

7. The distance between the objective lens and the specimen is called the ______ distance.

A. working B. viewing C. objective D. functional

A. working

8. Which of the following components of the compound microscope is used to focus light on the specimen?

A. draw tube B. illuminator C. iris diaphragm D. condenser

D. condenser.

9. What is the magnification of the transmission electron microscope (TEM)?

A. 10–1,500X B. 10–3,000X C. 10–500,000X D. 200–1,000,000X

D. 200–1,000,000X

10. The scanning electron microscope (SEM) is useful for studying which of the following?

A. The surface features of specimens.

B. The finer details of the internal structures of organisms.

C. The ultrastructure of cells.

D. Certain biochemicals

A. The surface features of specimens.

11. To change the amount of light entering the objective lens, you would adjust the________.

A. nosepiece B. condenser C. iris diaphragm D. light source

C. iris diaphragm

12. While looking at a specimen under a microscope, you move the slide to the right. In which direction does the image move?

A. to the right B. to the left C. up D. down

B. to the left

13. What would you do in order to view a fresh specimen under the microscope?

A. Place the specimen in a drop of oil.

B. Place the objective directly into the specimen without a coverslip.

C. Treat the specimen with heavy metal salts.

D. Prepare a wet mount

D. Prepare a wet mount.

14. You are looking at a specimen through a high-power objective with a magnification of 45X, and the ocular has a magnification of 10X. What is the total magnification?

A. 45X B. 450X C. 4,500X D. 45,000X

B. 450X

15. Which of the following indicates the highest resolution (detail)?

A. 5–10 nanometers

B. 200 nanometers

C. 300 nanometers

D. 500 nanometers

A. 5–10 nanometers

16. The thickness of a specimen in focus at any one time is known as _____ and can be shown by using a _________.

A. depth of field, slide containing three different colored threads

B. working distance, slide containing three different colored threads

C. plane of focus, slide containing three different colored threads

D. depth of field, letter “e” slide

A. depth of field, slide containing three different colored threads

17. Care must be taken using the oil-immersion objective. Which of the following steps are essential to care properly for this objective?

A. Clean the oil off of the oil-immersion objective carefully.

B. Start by focusing on the low objective and moving up gradually to the oil-immersion lens.

C. Only use the fine adjustment knob when focusing the oil-immersion lens.

D. All of the above

D. All of the above.

18. The Nomarski microscope __________.

A. produces nearly 3-dimensional images C. uses electrons

B. uses ultraviolet light D. requires the use of fluorescent dyes

A. produces nearly 3-dimensional images

19. When using the _____ objective, you would use the coarse-focus adjustment knob to bring the specimen into focus.

A. oil-immersion

D. scanning

B. high-power

E. C and D

C. low-power

D. scanning

20. What should you do if you want to change the objective?

A. Grasp the desired objective and pull it into place.

B. Turn the nosepiece.

C. Turn the fine-focus adjustment knob.

D. Move the slide under the desired objective

B. Turn the nosepiece.

21. Which objective would you use to search for a specimen?

A. scanning B. low-power C. high-power D. oil-immersion

A. scanning

22. You are looking at a specimen under low power, and you switch to the high-power objective. Which of the following happens?

A. The magnification decreases.

C. The amount of light decreases.

B. The resolution increases.

D. You can no longer see the specimen

C. The amount of light decreases.

23. If you change from the low-power objective to the high-power objective, what happens to the depth of field?

A. increases B. decreases C. no change D. completely lost

B. decreases

24. What happens to the field of view if you switch from the high-power objective to the low-power objective?

A. disappears B. no change C. decreases D. increases

D. increases

25. You place a translucent ruler under your microscope at low power, and the field of view measures 7 millimeters. What is the diameter of the field of view for the low-power objective?

A. 70 micrometers

C. 7,000 micrometers

B. 700 micrometers

D. 70,000 micrometers

C. 7,000 micrometers

26. When using the high-power and oil-immersion objectives, the working distance ____, so ____ light is needed.

A. decreases, more

B. decreases, less

C. increases, more

D. increases, less

A. decreases, more

27. The _____ microscope accents minute differences in the refractive index of structures within a specimen.

A. simple light B. phase contrast C. bright field D. all of these

B. phase contrast

28. Which formula would you use to determine the diameter of the field of view for the high-power objective?

A. HPD = [LPD × LPM]/HPM

C. HPD = [LPD + LPM] × HPM

B. HPD = [LPD/LPM] × HPM

D. HPD = [LPD × HPM]/LPM

A. HPD = [LPD × LPM]/HPM

29. In order to estimate the size of the specimen, you need to calculate the ________.

A. working distance

C. diameter of the field of view

B. magnification power of the objective

D. depth of field

C. diameter of the field of view

30. When changing objectives using a parfocal microscope, you would only need to make a minor adjustment in the _____.

A. distance between the oculars C. focus

B. position of the slide D. amount of light

C. focus