3.2 - The electron Microscope Flashcards
What are the main advantages of using an electron microscope?
The electron beam has a very short wavelength and the microscope can therefore resolve objects well – it has a high resolving power.
As electrons are negatively charged the beam can be focused using electromagnets.
Why must electron microscopes be under a vacuum?
Because electrons are absorbed or deflected by molecules in the air, and a vacuum has to be created within the chamber of an electron microscope in order for it to work effectively.
What are the two types of electron microscope?
The transmission electron microscope TEM
The scanning electron microscope SEM
How does The TEM microscope work?
An electron gun produces a beam of electrons that is focused on the specimen by an electromagnet. Parts of the specimen absorb electrons and therefore appear dark other parts allow the electrons to pass through and so appear bright.
