Magnification Flashcards
What is magnification?
How large an image is compared to real life
What is resolution?
The amount of information that can be seen in an image it is defined as the smallest distance below which two discrete object will be seen as one.
How can you work out image size?
actual size * magnification
What is a light microscope?
-Maximum magnification of light microscopes is usually ×1500, and their maximum resolution is 200nm, due to the wavelength of light
An advantage of the light microscope is that it can be used to view a variety of samples, including whole living organisms or sections of larger plants and animals
- It is also relatively inexpensive
-specimens require preparation before being viewed by a light microscope, as some may not be coloured or might distort when cut.
What is an electron microscope?
Electrons have a much lower wavelength than light which means that they can be used to produce an image with resolution as great as 0.1nm. Electron Microscopes can have magnifications of ×500000.
There are different types of Electron Microscope. A Transmission Electron Microscope (TEM) produces a 2D image of a thin sample, and has a maximum resolution of ×500000.
A Scanning Electron Microscope (SEM) produces a 3D image of a sample by ‘bouncing’ electrons off and detecting them at multiple detectors. It has a maximum magnification of about ×100000.
samples must be placed in a vacuum as electrons are deflected by particles in the air
they are very expensive to buy and maintain, and preparing the samples requires a lot of skill to do.
