ch.1 lab

Question 1

body tube

Answer 1

transmits the image from the objective lens to the ocular lens

Question 2

ocular lens (eyepiece)

Answer 2

remagnifies the image formed b the objective lens

Question 3

objective lenses

Answer 3

primary lenses that magnify the specimen

Question 4

mechanical stage

Answer 4

holds the microscope

Question 5

diaphragm

Answer 5

controls the amt of light entering the condenser

Question 6

illuminator

Answer 6

light source

Question 7

fine focusing knob

Answer 7

used for focusing the specimen; turning the know changes the distance between the objective lens and the specimen

Question 8

light intensity

Answer 8

adjusts current to lamp

Question 9

oil immersion lens

Answer 9

highest magnification (97Xto 100X) must be used with immersion oil

Question 10

“resolution/

resolving power”

Answer 10

the ability of lenses to reveal fine detail or two points distinctly separated

Question 11

refractive index

Answer 11

the amt the light bends

Question 12

spherical aberration

Answer 12

when you bring the center of the microscope field into focus, the periphery may be fuzzy because of the curvature of the lens resulting in multiple focal pts

Question 13

chromatic aberration

Answer 13

the lens may give each wavelength of light a different focal pt

Question 14

iris diaphragm

Answer 14

controls the angle and size of the cone of light in the Condenser; ability to control the amt. of light ensures that optimal light will reach the slide

Question 15

condenser

Answer 15

above the light source, consists of several lenses that concentrate light on the slide by focusing it into a cone

Question 16

parfocal

Answer 16

a subject is in focus w/ one lens, it will be in focus w/all lenses

Question 17

which biosafety level is appropriate wen handling human body fluids in microbiology lab?

Answer 17

BSL-2

Question 18

what kind of microscope consisted of biconvex lenses and were essentially magnifying glasses

Answer 18

simple microscopes

Question 19

what microscope is required to see microbes and has two lenses between the eye and the object

Answer 19

compound microscope

Question 20

which microscope shows dark objects in a bright field and is used most often

Answer 20

brightfield compound microscope

Question 21

microscope with only one ocular lens

Answer 21

monocular microscope

Question 22

has two ocular lenses

Answer 22

binocular microscope

Question 23

larger knob, used for focusing with the lower power objectives (4X and 10X)

Answer 23

coarse adjustment

Question 24

smaller knob, used for focusing with the high power and oil immersion lenses

Answer 24

fine adjustment

Question 25

area seen thru the microscope

Answer 25

field of vision

Question 26

most important lense in microbio, has the highest magnification (97x to 100x)

Answer 26

oil immersion lens

Question 27

what can be adjusted with a wheel that regulates the amount of current to the bulb

Answer 27

intensity

Question 28

what requires more light

Answer 28

higher magnification

Question 29

the resolving power is a function of the wavelength of light used and a characteristic of the lens system called ?

Answer 29

numerical aperture

Question 30

what is the resolving power of a light microscope

Answer 30

about 200nm

Question 31

what is the resolving power of an electron microscope

Answer 31

less than .2nm

Question 32

what does increasing the numerical aperture do

Answer 32

improves the resolving power

Question 33

what is important about the glass microscope slide and immersion oil

Answer 33

they have the same refractive index, the oil keeps the light rays from refracting

Question 34

focal point

Answer 34

light rays pass thru a lens, they are bend to converge at the focal point, where an image is formed

Question 35

spherical aberration

Answer 35

when you bring the center of a microscope field into focus, the periphery may be fuzzy because of the curvature of the lens, resulting in multiple focal points

Question 36

how can spherical aberration be minimized

Answer 36

by using the iris diaphragm, which eliminates light rays to the periphery of the lens, or by a series of lenses resulting in essentially a flat optical system

Question 37

chromatic aberration

Answer 37

multitude of colors seen in the field caused by prismlike effect of the lens as various wavelengths of white light pass thru to a different focal pt for each wavelength

Question 38

how can chromatic aberrations be minimized

Answer 38

by using filters(usually blue); or by lens systems corrected for red and blue light(achromatic lenses); or by lenses corrected for red, blue and other wavelengths(apochromatic lenses

Question 39

most expensive method of eliminating chromatic aberrations is to used a light source of one wavelength called ?

Answer 39

monochromatic light

Question 40

what do you do before using the oil immersion lens

Answer 40

always focus with low power first

Question 41

how does increased magnification affect the field of vision?

Answer 41

the image becomes less focused

Question 42

why is it desirable that microscope objectives be parfocal?

Answer 42

the slide remains in focus when switching from a lower magnification to a higher magnification level

Question 43

which objective focuses closest to the slide when it is in focus

Answer 43

oil immersion

Question 44

is our lens corrected for chromatic aberrations?

Answer 44

no

Question 45

name two ways in which you can enhance the resolving power?

Answer 45

by decreasing the wavelengths of light and increasing the numerical aperture

Question 46

what are the advantages of the low power objective over the oil immersion objective for viewing fungi or algae?

Answer 46

adv. of the low power objective is that you are able to see the entire cell of the fungi or algae, there is a larger field of vision, and the cells and their structures can be seen more clearly

Question 47

what would occur if water were accidentally used in place of immersion oil?

Answer 47

the light ray would be refracted because water does not have the same refractive index as glass