Quiz: Microscope

Question 1

What is the function of the fine focus knob? Where is it located?

Answer 1

It raises and lowers the stage to refine the focus. It is located on the side of the microscope; it looks like a smaller knob located on top of a bigger knob.

Question 2

What is the function of the coarse focus knob? Where is it located?

Answer 2

It raises and lowers the stage to bring the specimen into view and focus it. It is located on the side of the microscope; it looks like a bigger knob located next to a smaller knob (fine focus knob).

Question 3

What is the function of the iris diaphragm? Where is it located?

Answer 3

It controls the amount of light passing through the specimen. It is located in the condenser, which is below the mechanical stage.

Question 4

What is the function of the ocular lens? Where is it located?

Answer 4

It further magnifies the image produced within the microscope by the objective lens. It is the eyepiece sitting atop the microscope.

Question 5

What is the function of the scanning objective? Where is it located?

Answer 5

((4x) It magnifies the object being observed and produces an image within the microscope. It is located above the mechanical stage, labeled 4x.

Question 6

What is the function of the low power objective? Where is it located?

Answer 6

(10x) It magnifies the object being observed and produces an image within the microscope. It is located above the mechanical stage, labeled 10x.

Question 7

What is the function of the high power objective? Where is it located?

Answer 7

(40x) It magnifies the object being observed and produces an image within the microscope. It is located above the mechanical stage, labeled 40x.

Question 8

What is the function of the mechanical stage? Where is it located?

Answer 8

It holds the slide in place. It is located below the objective lens.

Question 9

Calculate the total magnification of a microscope that has a 10x ocular and the following objective lenses in the viewing position.

4x
10x
40x

Answer 9

(4x) * (10x) = 40x
(10x) * (10x) = 100x
(40x) * (10x) = 400x

Question 10

Which objective lens should you always start with?

Answer 10

Low power

Question 11

Explain why the specimen should always be centered when switching to a higher power lens.

Answer 11

It is easier to focus and locate the specimen under low power, and when you switch to a higher power, the image is nearly in focus with only minor adjustments.

Question 12

Explain why specimens need to be thin for viewing under the microscope.

Answer 12

More light penetrates them, giving a much clearer image through the microscope.

Question 13

Explain why the coarse focus knob should never be used when the high power objective is in the viewing position.

Answer 13

The image moves in and out too quickly, so it’s difficult to adjust the focus.

Question 14

Why are the microscope lenses cleaned only with lens paper and special cleaning solution?

Answer 14

The lenses are easier to scratch because they are softer than ordinary glass.

Question 15

Draw the letter “P” as it would appear when viewing under the microscope?

Answer 15

It is flipped upside down and looks like a backwards “P”.

Question 16

When you move the slide to the right, the image moves to the ____.

Answer 16

Left.

Question 17

Which lens has the greatest diameter of field?

Answer 17

Low power

Question 18

Which lens has the least diameter of field?

Answer 18

40x

Question 19

Dissecting microscopes are used for…

Answer 19

Viewing relatively large opaque objects such as plants, insects, and other small animals.

Question 20

Electron microscopes are used in…

Answer 20

Research laboratories and are powerful enough to show the crude structure of some large molecules like proteins.

Question 21

Compound microscopes are…

Answer 21

The most common. They are made up of two lenses: the ocular lens and the objective lens.

Question 22

Which objective lens should be in place when the microscope is put away?

Answer 22

Scanning

Question 23

What is magnification?

Answer 23

Magnification is the ability of the lens to enlarge the visual image of the object.

Question 24

What is the resolving power?

Answer 24

Resolving power is the ability of a microscope to distinguish fine detail.

Question 25

Convert 2.2 mm into microns (u).

Answer 25

2200 (u)

Question 26

Convert 500 microns into mm.

Answer 26

0.5 mm

Question 27

Explain how you would measure a specimen under a microscope with a known diameter of field?

Answer 27

If you know the diameter of field, you can estimate the size of the objects seen under the microscope by comparing them to the known diameter of field. For example, if you’re observing a flea under low power and it appears to be 2/3 of the way across the field of view, assume the diameter of field is 1800 microns (u).

Multiply 2/3 * 1800 (u) = 1200 (u).