Microscopy

Question 1

real image

Answer 1

formed by the objective
object is beyond the focal point of the lens
image is INVERTED, MAGNIFIED
on the opposite side of the lens from the object

Question 2

virtual image

Answer 2

formed by the eyepiece
object is inside the focal point of lens
UPRIGHT, MAGNIFIED
located on the same side of the lens as the object

Question 3

resolving power

Answer 3

the ability of a microscope to see minute detail

Question 4

Resolution

Answer 4

the smallest distance between two points which the microscope can see
- differentiate them as two points rather than one (i.e. do not blur together)

Question 5

T or F. As resolving power increases or gets better, the value of resolution decreases

Answer 5

T!
this means that the microscope is better able to differentiate between two objects that are close together and better able to see fine detail

Question 6

T or F. One can see more detail with the shortest wavelength (violet) than the longest wavelength (red)

Answer 6

T! if wavelength becomes smaller (numerator), resolution will become a smaller number (resolving power improves)

Question 7

a measure of the light-gathering potential of a lens

Answer 7

numerical aperture
- describes the maximum angle from which the lens can accept light
- a result of the combined effect of: lens aperture & the medium between lens and object

Question 8

the distance from the object to the front of the objective lens when the object is in focus

Answer 8

working distance
- not the same as focal length
- working distance depends on focal length of the lens
- the longer the focal length, the greater the working distance
- size of aperture affected by working distance

Question 9

As working distance decreases, what happens to 1/2 angle of aperture of the objective lens and NA?

Answer 9

both increase

Question 10

an expression of the optical density of a medium

Answer 10

refractive index

Question 11

the ratio of refractive index

Answer 11

speed of light (in air or vacuum) : the speed of light in a medium (eg. immersion oil)

Question 12

T or F. as refractive index increases, so will NA

Answer 12

T! so will resolving power

Question 13

wide angle oculars

Answer 13

“w”
allow a larger field of view

Question 14

high eyepoint oculars

Answer 14

focus the image a higher distance above the top of the lens of the eyepiece so that the ocular can comfortably be used when eyeglasses are worn

Question 15

two functions of the substage condenser

Answer 15

provides even illumination of high intensity from a high angle and it concentrates light onto the specimen

Question 16

iris diaphragm

Answer 16

• shutter arrangement that controls the angle of the beam of light focused onto the specimen
• this angle determines the NA of the condenser

Question 17

iris diaphragm

Answer 17

• shutter arrangement that controls the angle of the beam of light focused onto the specimen
• this angle determines the NA of the condenser

Question 18

flip-out lens

Answer 18

used with 40X, 50X, 100X
increases the NA of the condenser by increasing te cone of light which goes into the objective

Question 19

total magnification

Answer 19

multiply the mag of the ocular by mag of the objective

Question 20

empty magnification

Answer 20

means that the increased magnification of an object without increased resolving power or increased detail (image starts to appear fuzzy)