Microscopes 🔬 Flashcards
1
Q
What are the 2 main advantages of the electron microscope?
A
- Short wavel. so good resolution
- Electrons are neg. charged so electromagnets can be used.
2
Q
What are the 2 types of EM?
A
SEM & TEM
3
Q
TEM - What is the resolving power?
A
0.1nm
4
Q
SEM - What is the resolving power?
A
20nm
5
Q
Why can the EM resolve objects better than the light M.?
A
EM uses a beam of electrons that has a much smaller wavelength than light.
6
Q
Why is a vacuum needed in an EM?
A
Electrons are absorbed by air molecules so if present, the electrons would not reach the specimen.
7
Q
TEM - What are the issues?
A
- Living specimens can’t be observed
- Complex staining process
- Image may be obstructed by artifacts
8
Q
TEM - What are the images like?
A
- Black and white
- 2D
9
Q
SEM - What are the images like?
A
- Coloured after scanning process
- 3D
