Microscopy Flashcards
Magnification calculation
Magnification = image / actual
Magnification definition
Number of times larger an image is, compared with the actual size of the object
How many millimetres is 1 metre
1000
How many micrometers is 1 millimetre
1000
How many nanometers is 1 micrometer
1000
Resolution and magnification definition
-resolution
How much detail you can see , or if you can see 2 points that are really close together
-magnification
How many times bigger the image is that the actual object
Why do we use electron microscopes?
Better resolution and magnification
Radiation used in light microscopes
Light rays
Radiation used in electron microscopes
Electron beam
How to focus a light microscope
Lens
How to focus electron microscopes
Magnets
What are the different types of electron microscope?
- Scanning electron microscope (SEM)
- Transmission electron microscope (TEM)
Biological matter studied by a light microscope
Living or dead
Biological matter studied by an electron microscope
Dead
Size of light microscope
Small and portable
Size of electron microscope
Very large and static
Ease of use for light microscope
Very easy
Ease of use for electron microscope
Skill and training required
Cost of light microscope
Relatively cheap
Cost of electron microscope
Very expensive
Can light microscopes use samples in a vacuum?
No
Can electron microscopes use samples in a vacuum?
Yes
Type of image from a light microscope
2D
Type of image from TEM
2D (cross section)
Type of image from SEM
3D
Magnification of light microscope
X1500
Magnification of TEM
X500 000
Magnification of SEM
X100 000
Why is having the highest magnification not always better? (2)
- won’t focus properly
- you can see limited number of cells
Resolving power of a light microscope
200nm
Resolving power of a TEM
0.2nm
Resolving power of a SEM
10nm
How does a TEM work?
-send electrons through through a specimen
How does a SEM work?
-bounce electrons off the surface of an object
Resolving power of a light microscope
200nm
Resolving power of a TEM
0.2nm
Resolving power of a SEM
10nm
How does a TEM work?
-send electrons through through a specimen
How does a SEM work?
-bounce electrons off the surface of an object
How to work out total magnification
Eyepiece lens x objective lens