Midterm exam

Question 1

Agar

Answer 1

a carbohydrate derived from seaweed used to solidify a liquid medium
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Question 2

media

Answer 2

the substances used to support growth of microorganisms

Question 3

Anton Van Leeuwenhoek

Answer 3

first mircroscope with only one lens. many disadvantages

Question 4

Todays microscopes have at least how many lens

Answer 4

2 , ocular and objective

Question 5

does the ocular lens have magnification abilities

Answer 5

yes

Question 6

How do you obtain total magnification

Answer 6

multiply ocular x objective

Question 7

Ernest abbe

Answer 7

developed third lens, called condenser

oil immersion technique

Question 8

What does oil do

Answer 8

helps to decrease the loss of transmitted light which in turn increases image clarity

Question 9

Did ernest abbe reduce both types of abbreations?

Answer 9

jes

Question 10

made what kind of lens too

Answer 10

concave to form flat image to overcome aberrations

Question 11

Spherical Lens Aberrations

Answer 11

light rays passing through the edge of a convex lens are bent more than light rays passing through the center. to fix: place the diaphrahm below the lens so that only the center of the lens is used.

Question 12

Chromatic Lens aberrations

Answer 12

disstortions of colors. Blue is bent more so goes less of a distance. red is formed outside.

Question 13

Apochormatic lens

Answer 13

free of both aberrations

Question 14

achromatic lens

Answer 14

free of chromatic abberrations

Question 15

human eye power

Answer 15

.1 mm

Question 16

power of light microscope

Answer 16

.2 um

Question 17

how is resolving power related to wavelength

Answer 17

as wavelegth decreases, power increases

Question 18

how is power related to numerical aperture of condensor and objective

Answer 18

increase and increase

Question 19

numerical aperture is what

Answer 19

n sin theta, n is refractive index

Question 20

refractive index is what

Answer 20

medium employed between the objective lens and the upper slide surface as well as the medium employed between the lower slide surface and the condenser lens. air is 1 oil is 1.25 or 1.56

Question 21

what is sin theta

Answer 21

the max angle formed by the light rays coming from the condenser and passing through the specimen into the front lens of the objective

Question 22

focal length

Answer 22

distance from the principal point of focus of the objective lens to the principal point of focus of the specimen

Question 23

working distance

Answer 23

distance between lens and specimen

Question 24

the shorter the working distance, the blank the opening of the condenser iris diaphragm required from proper illumination

Answer 24

larger

Question 25

Iris diaphragm

Answer 25

an adjustable opening that can be used to regulate the aperture of a lens

Question 26

parfocal

Answer 26

having a set of objectives so mounted on the microscope that they can be interchanged without having to appreciably vary the focus

Question 27

refractive index

Answer 27

the ratio of the velocity of light in the first of two media to its velocity in the second medium as it passes from one medium to another medium with a different index refraction

Question 28

functions of substage condenser

Answer 28

provides parallel rays of light and focuses them on the surface of the slide