Microscopy Lab

Question 1

What is the purpose of the ocular lens in a microscope?

Answer 1

To magnify the image by an additional 10X

The ocular lens is where you place your eye to view the specimen.

Question 2

What are the four objective lenses on a student microscope?

Answer 2

• 4X (scanning lens/red collar)
• 10X (low power lens/gold collar)
• 40X (high power lens/blue collar)
• 100X (oil immersion lens/white collar)

Each objective lens has a specific magnification power stamped on it.

Question 3

What is the maximum magnification power of the light microscope?

Answer 3

1000 times

This is achieved by combining the objective lens magnification with the ocular lens magnification.

Question 4

Define resolution in the context of microscopy.

Answer 4

Sharpness of the image and the ability to see separate structures as distinct

Resolution is crucial for distinguishing between closely spaced structures.

Question 5

What does contrast refer to in microscopy?

Answer 5

The capability of a microscope to maintain the clarity of a specimen against its background

Contrast affects how well the specimen is viewed against its background.

Question 6

True or False: The coarse adjustment knob should be used with high-powered objective lenses.

Answer 6

False

The fine adjustment knob should be used for high-powered lenses.

Question 7

What is the function of the mechanical stage?

Answer 7

To hold the slide in place and allow for positioning of the specimen

It contains clips to secure the slide.

Question 8

Fill in the blank: The _______ is located just underneath the stage and focuses the light beam before it encounters the specimen.

Answer 8

[condenser]

Question 9

What happens to the field of view (FOV) as magnification increases?

Answer 9

FOV decreases

As you switch to higher magnification, the area you can see becomes smaller.

Question 10

What is the function of the iris diaphragm lever?

Answer 10

To adjust the intensity of the light beam

It is located just underneath the stage.

Question 11

Which objective lens has the shortest working distance?

Answer 11

100X (oil immersion lens)

The working distance decreases with increasing magnification.

Question 12

How do you begin viewing a slide specimen?

Answer 12

Start with the scanning objective (4X)

This lens has the longest working distance and is safest for initial focusing.

Question 13

What is the total magnification when using the 40X objective lens?

Answer 13

400X total magnification

This is calculated by multiplying the objective lens power by the ocular lens power (40X * 10X).

Question 14

What should you do after completing your viewing of the slide?

Answer 14

Remove the last slide and return it to the instructor

Ensure the 4X objective is in position and the stage is lowered.

Question 15

What is the depth of field in microscopy?

Answer 15

The thickness of the specimen that is in focus at one time

Higher magnification results in a lower depth of field.

Question 16

What happens to the specimen when you move it to the left using the mechanical stage manipulator knobs?

Answer 16

It appears to move to the right

This is because the motion is reversed in the ocular lens.

Question 17

Match the microscope part to its function: This supplies light for viewing.

Answer 17

[light source]

Question 18

Match the microscope part to its function: This is the bottom portion of the microscope that is grasped when carrying it.

Answer 18

[base]

Question 19

Match the microscope part to its function: This cylinder joins the eyepiece to the arm.

Answer 19

[body tube]

Question 20

Match the microscope part to its function: Only focus knob that should be used when using the high power or oil immersion lenses.

Answer 20

[fine adjustment knob]

Question 21

Match the microscope part to its function: Initial knob used to focus an image when the scanning or low power objectives are selected.

Answer 21

[coarse adjustment knob]

Question 22

What is the orientation difference observed when viewing a slide with the letter ‘e’?

Answer 22

The letter appears inverted

This is due to the optics of the microscope.