Magnification And Microscopes

Question 1

How do you get from mm to micrometers to nm

Answer 1

X1000, x1000. /1000 the other way

Question 2

Magnification equation

Answer 2

Size of image/actual size

Question 3

Define magnification

Answer 3

How much bigger a sample appears to be under the microscope than in real life

Question 4

Define resolution

Answer 4

The ability to distinguish between two points on an image

Question 5

Equation for overall magnification

Answer 5

Objective lense x eyepiece lense

Question 6

Why is the resolution of a light microscope lower than an electron microscope

Answer 6

The wavelength of light is much larger than the wavelength of electrons

Question 7

Advantage of an electron microscope

Answer 7

+ resolution is x2000 more than light microscopes
+ produces detailed images
+ sem produces 3D images

Question 8

Disadvantages of an electron microscope

Answer 8

• samples have to be placed in a vacuum
• very expensive
• need to be skilled to create samples
• complex staining process
• image may contain artefacts (impurities)

Question 9

How do transmission electron microscopes work

Answer 9

They pass a beam of electrons through a specimen, the electrons are focused by magnets amd the ones that pass through are detected on a fluorescent screen

Question 10

Limitations of TEM

Answer 10

Thin sections of specimen needed for electron to be able to pass through(as thin as a nanometer)
Flat 2D image

Question 11

How does a scanning electron microscope work

Answer 11

Pass a beam of electrons over the surface of the specimen. electrons are reflected off the surface as it has been coated in heavy metals or metal salts. Produces a 3D image

Question 12

Limitations of a SEM

Answer 12

Resolution and magnification is lower than a TEM

Question 13

Which has a higher resolution TEM or SEM

Answer 13

TEM