Q: If the field diameter under a 4x objective is 4 mm, what is the estimated field diameter under a 40x objective? Use the formula $$D_1$$ \times $$M_1$$ = $$D_2$$ \times $$M_2.$$

$$D_2$$ = \frac{$$D_1$$ \times $$M_1$$}{$$M_2$$} = \frac{4 \times 4}{40} = 0.4$$ mm

Q: If a specimen extends halfway across a field diameter of 2 mm, what is its estimated size in micrometers?

$$2 \text{ mm} \div 2 = 1 \text{ mm} = 1000 \text{ \mu m}$$

Q: A student wants to estimate the size of a cell under the microscope. The field diameter is 1.5 mm and the cell covers one-third of the field. What is the cell's approximate size in micrometers?

$$1.5 \text{ mm} \div 3 = 0.5 \text{ mm} = 500 \text{ \mu m}$$

Question 1

Which part of the compound microscope is responsible for controlling the amount of light that reaches the specimen?

Accepted Answer

Iris diaphragm lever

Question 2

A student is using a compound microscope with a 10x ocular lens and a 40x objective lens. What is the total magnification?

Accepted Answer

$$10 	imes 40 = 400$$

Question 3

When switching from a low power objective lens to a high power objective lens, what happens to the field diameter?

Accepted Answer

It decreases

Question 4

Why should you only use the coarse adjustment knob with the lowest power objective lens?

Accepted Answer

To prevent damaging the slide or lens due to limited working distance at higher magnifications

Question 5

If the field diameter under a 4x objective is 4 mm, what is the estimated field diameter under a 40x objective? Use the formula $$D_1$$ 	imes $$M_1$$ = $$D_2$$ 	imes $$M_2.$$

Accepted Answer

$$D_2$$ = \frac{$$D_1$$ 	imes $$M_1$$}{$$M_2$$} = \frac{4 	imes 4}{40} = 0.4$$ mm

Question 6

Which of the following best describes 'resolution' in microscopy?

Accepted Answer

The ability to distinguish two close points as separate entities

Question 7

A specimen appears blurry under high power, but is clear under low power. What is the most likely cause?

Accepted Answer

The coarse adjustment knob was used with the high power objective

Question 8

Which part of the microscope should you hold when carrying it?

Accepted Answer

One hand on the arm and the other supporting the base

Question 9

If a specimen extends halfway across a field diameter of 2 mm, what is its estimated size in micrometers?

Accepted Answer

$$2 	ext{ mm} \div 2 = 1 	ext{ mm} = 1000 	ext{ \mu m}$$

Question 10

What is the function of the condenser in a compound microscope?

Accepted Answer

It focuses light onto the specimen

Question 11

Which statement about depth of field in microscopy is correct?

Accepted Answer

Depth of field decreases as magnification increases

Question 12

A student wants to estimate the size of a cell under the microscope. The field diameter is 1.5 mm and the cell covers one-third of the field. What is the cell's approximate size in micrometers?

Accepted Answer

$$1.5 	ext{ mm} \div 3 = 0.5 	ext{ mm} = 500 	ext{ \mu m}$$

Question 13

Which of the following is NOT a recommended handling instruction for a compound microscope?

Accepted Answer

Swing the instrument by the arm when transporting

Question 14

What is the primary function of the mechanical stage controls on a compound microscope?

Accepted Answer

To move the slide smoothly and precisely for viewing different areas

Question 15

If the total magnification is 100x and the field diameter is 2 mm, what will the field diameter be at 400x magnification? Use the formula $$D_1$$ 	imes $$M_1$$ = $$D_2$$ 	imes $$M_2.$$

Accepted Answer

$$D_2$$ = \frac{2 	imes 100}{400} = 0.5$$ mm

Question 16

Which lens should you use to begin focusing a specimen on a compound microscope?

Accepted Answer

Lowest power objective lens

Question 17

What is the correct sequence for cleaning the lenses of a compound microscope?

Accepted Answer

Use lens paper only, clean in a circular motion before and after use

Question 18

Which of the following best explains why specimens are measured in micrometers and millimeters under the microscope?

Accepted Answer

Because most specimens are too small to be measured in centimeters or inches

Question 19

What is the function of the rotating nosepiece on a compound microscope?

Accepted Answer

To switch between different objective lenses

Question 20

Which of the following is a consequence of increasing magnification on a compound microscope?

Accepted Answer

Field diameter and depth of field both decrease

Microscopy: Structure, Use, and Principles for Anatomy & Physiology

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