Midterm 1

Question 1

Why is the microscope we use called a compound microscope?

Answer 1

The transmitted light passes through two magnifying lenses before reaching each of the investigator’s retinas and the magnification is compounded.

Question 2

What power is the High-Power objective?

Answer 2

40X, and used for fine and final focusing.

Question 3

What power is the low-power objective?

Answer 3

10X, used for coarse focusing or final focusing.

Question 4

What power is the scanning objective?

Answer 4

4X. Used for initial viewing and adjustment.

Question 5

What power is the oil immersion objective?

Answer 5

100X. Used for very small specimens.

Question 6

How do you calculate the magnification of a specimen?

Answer 6

It’s the product of the power of the ocular lens (10X) and the power of the objective lens.

Question 7

What is the total magnification of the microscope when you’re using the high-power objective?

Answer 7

10X times 40X = 400X

Question 8

What is the total magnification of your microscope when you’re using the scanning objective?

Answer 8

10X times 4X = 40X

Question 9

What is the total magnification of your microscope when you’re using the oil immersion lens?

Answer 9

10X times 100X = 1000X

Question 10

What is a microscope’s “resolving power,” and what is the exact resolving power of the oil immersion lens?

Answer 10

Resolving power is the smallest distance between two points on a microscope’s field of view that can be distinguished as distinct entitities.
The oil immersion lens has a resolving power of 200 nm.

Question 11

How does the image orientation come across in a microscope?

Answer 11

It’s upside down from the actual orientation, and it moves the opposite way you physically move it.

Question 12

True or False: The greater the magnification, the greater the illumination that is required to view the specimen.

Answer 12

True. The iris diaphragm regulates the amount of light entering and in return regulates contrast.

Question 13

What does the “working distance” of the microscope refer to?

Answer 13

It refers to the vertical distance between the objective lens you are using and your specimen. Need more light when the objective lens is closer and/or in greater magnification.

Question 14

What is the actual distance for 1 interval on an ocular micrometer at the 4X objective?

Answer 14

25 micrometers/1 interval

Question 15

What is the actual distance for 1 interval on an ocular micrometer at the 10X objective?

Answer 15

10 micrometers/1 interval

Question 16

What is the actual distance for 1 interval on an ocular micrometer at the 40X objective?

Answer 16

2.5 micrometers/1 interval

Question 17

What is the actual distance for 1 interval on an ocular micrometer at the 100X objective?

Answer 17

1 micrometer/1 interval

Question 18

Is the working distance greater when using the 40X or 10X objective lens?

Answer 18

Greater when using 10X.

Question 19

What is the “depth of field” of a microscope?

Answer 19

It is the thickness of the specimen that is in focus at any one time.

Question 20

True or False: The greater the magnification, the less the depth of field

Answer 20

True.

Question 21

Can you focus on all plans of a specimen at one time using the scanning objective?

Answer 21

Yes

Question 22

Can you focus on all planes of a specimen at one time using the 40X objective?

Answer 22

No

Question 23

Does the 4X or 40X objective have a shallower depth of field?

Answer 23

40X

Question 24

Does a deeper plan or more superficial plane come into focus first?

Answer 24

Superficial

Question 25

Does the 10X or 40X objective have a shallower depth of field?

Answer 25

40X