3-1

Question 1

what are the components of the microscope?

Answer 1

1. on and off switch
2. substage condenser
3. iris diaphragm
4. stage
5. mechanical stage
6. objective lens
7. revolving nose piece
8. ocular lens
9. turret and set screws
10. coarse and fine coarse knobs
11. stage clip

Question 2

What does the substage condenser do?

Answer 2

condenses the beam of light onto the specimen

Question 3

what does the iris diaphragm do?

Answer 3

controls light intensity of beam on the specimen

Question 4

what does the stage do?

Answer 4

flat surface in which microscope slide rests

Question 5

what is the mechanical stage?

Answer 5

allows movement of slide in all directions

also allows minute movement of slide

Question 6

what is the objective lens?

Answer 6

magnifies the specimen and produces the real image

Question 7

How many objective lens are there?

Answer 7

four

4X (scanning) red
10X (low dry) yellow
40X (high dry) blue
100x (oil immersion) white

ron yelled beware whitney

Question 8

what is the revolving nose piece?

Answer 8

enables moving different objective lenses into position

Question 9

what is the ocular lens?

Answer 9

two ocular lens (binocular)
10X in power
allows adjustment for eye separation and focusing differences for each eye produces more magnification and a virtual image

Question 10

what are the turret and set screw?

Answer 10

allow loosening and rotation of oculars and locking of turret in position.

Question 11

what are the coarse and fine focus knobs?

Answer 11

focus adjustment
large knob: coarse adjustment (moves stage up and down)
small knob: fine focus

Question 12

what is the stage clip?

Answer 12

holds microscope slide to mechanical stage so that slide can be precisely positioned for viewing

Question 13

formula for total magnification?

Answer 13

ocular power x objective power

Question 14

what is resolution or resolving power?

Answer 14

the ability of the objective lenses to distinguish two points as clear and separate entities at a specific distance apart

clarity of an image

Question 15

what is the formula for resolution/ resolving power?

Answer 15

RP=0.5xLambda/N.A

0.5: constant
Lambda: wavelength of light used t illuminate specimen
N.A: numerical aperature sine theta x i

(sine theta is the angle between specimen and center and outer edge of objective lens)

(i is index of refraction. How the speed of light is changed as it moves through one material into the other. As a result light is bent or refracted)

Question 16

how does wavelength of light affect resolution of microscope?

Answer 16

shorter the wavelength, the better the resolution

Question 17

when is immersion oil used?

Answer 17

100X objective

Question 18

why is immersion oil used?

Answer 18

to change the index of refraction to improve the resolution of the microscope

reduces angle

Question 19

how does one carry/handle a microscope?

Answer 19

carry with both hands
one hand at the base
other hand at the arm

Question 20

how does one use the microscope?

Answer 20

1. carry with both hands
2. turn light on and adjust intensity to 3-4
3. open iris diaphragm
4. move 4x object into position
5. open stage clip. place slide in position
6. use coarse focus knob to bring stage to highest position
7. use coarse focus to bring specimen into focus
8. use focus knob to bring into sharp focus
9. adjust width of ocular lens
10. focus right ocular while left eye is closed
11. with both eyes open adjust left ocular until left eye focus is sharp with right eye
12. observe specimen
13. lower stage, remove slide
14. clean/ remove oil with lens paper using ethanol
15. dry lens
16. turn light intensity to its lowest, then turn off
17. wrap electrical cord
18. return to cabinet

Question 21

When using the microscope, if field of view is dark, what is wrong?

Answer 21

check to see if light is on
check that iris diaphragm is wide open
make sure objective is clicked into position

Question 22

when using microscope and the specimen is in focus on lower power objectives but not on higher power objectives, what is wrong?

Answer 22

smear is upside down

if so, wipe off immersion oil, turn smear right side up, add immersion oil, focus

Question 23

when specimen is right side up, you can see smear, but cannot get it in focus, what do you do?

Answer 23

focus smear with 10x objective SLOWLY

then add immersion oil and turn to 100x objective, and focus with fine focus slowly in one direction and then back in the other direction

Question 24

able to get smear or specimen in focus with 10x objective but not with 100x objective?

Answer 24

air bubble blocking 100x objective
turn 100x objective out and wipe off the oil

or
insufficient oil has been added to smear

or
100x objective not in oil

Question 25

sufficient light available for focusing on specimen with 10x objective, however insufficient light to see specimen with 100x objective?

Answer 25

increase light intensity

check that iris diaphragm is wide open

Question 26

cannot find specimen with any objective?

Answer 26

did not heat fix

specimen washed off microscope slide

Question 27

what are two ways that you can improve resolving power on microscope?

Answer 27

1. shorten wavelength of light

2. use immersion oil

Question 28

what does parfocal mean?

Answer 28

lens stay in focus when you change objective