Microscopy

Question 1

What are the important unit conversions?

Answer 1

M-mm= X1000
Mm-m= /1000
Mm -um = x1000
Um - mm = /1000
Um-nm = x1000
Nm-um-/1000

Question 2

What is the eyepiece graticule?

Answer 2

-100 divisions
-no units as it depends on which lens power is being used

Question 3

What is the stage micrometre?

Answer 3

-It has 100 divisions and the smallest division always represents 100 um
-the eyepiece graticule needs to be calibrated, you need to overlay the eyepiece graticule over a stage micrometre so the two scales lineup

Question 4

What is the radiation source of each type of microscope?

Answer 4

-TEM + SEM = electron
-Light= light

Question 5

What is the wavelength of each type of microscope?

Answer 5

-TEM+ SEM= 0.005nm
-Light= 400-700nm

Question 6

What lenses are used in each type of microscope?

Answer 6

-light = gloss
-T E M+ SEM= electromagnetic

Question 7

What specimen is used on each type of microscope?

Answer 7

-Light= living or non-living on slide
-TEM= Non living on small copper grid in vacuum
-S E M= non-living on metal disc with vacuum

Question 8

What is the maximum resolution of each type of microscope?

Answer 8

-light= 200nm
-TEM= 0.5nm
-S E M=3-10 nm

SEM has a higher resolution than TEM

Question 9

What is the maximum magnification of each type of microscope

Answer 9

-Light= 1500x
-TEm= 250,000x
-SEM= 100,000x
TEM have a higher magnification than SEM

Question 10

What is the type of image of each microscope?

Answer 10

-light= 2-D colour
-TEm= 2D and black-and-white
-SEM= 3-D, black and white, can be digitally enhanced to have colour

Question 11

What stains to each type of microscope make?

Answer 11

-light=coloured dyes
-T E M= impregnated with heavy metals
-SEM = coated with carbon or gold

Question 12

What is the definition of magnification?

Answer 12

-how much larger a sample appears to be compared to its actual size
Higher magnification =lower resolution

Question 13

What is the definition of resolution?

Answer 13

• The ability to distinguish two objects that are close together

Question 14

How do you work out magnification?

Answer 14

• M = i/a
  Look at scale bar,the unit on the bar is the actual size, measuring the scale bar to get image size

Question 15

What does a laser scanning confocal microscope have to do?

Answer 15

• Uses laser, high resolution, focused On image
• see different layers at different depths