Electron diffraction
A particle doesn’t diffract, but a wave does.
Because we usually model an electron as a particle, we wouldn’t expect it to be able to diffract - but it does.
The experiment
If we pass a ray of electrons at a high voltage, for example,
That shows that electrons can behave like a wave!
This shows something called wave particle duality.
Diffraction and voltage
- If we increase the voltage of the electron beam, then the electrons are diffracted less - so they spread out less.
- Similarly, if we decrease the voltage of the electron beam, then the electrons are diffracted more - so they spread out more.
flashcards
| Question | Answer |
|---|---|
| Electron diffraction: What property of an electron is demonstrated by its ability to diffract? | Wave-particle duality. |
| What happens to electron diffraction when the voltage of the electron beam is increased? | The electrons are diffracted less, so they spread out less. |
| What happens to electron diffraction when the voltage of the electron beam is decreased? | The electrons are diffracted more, so they spread out more. |
| Electron diffraction: How do you demonstrate electron diffraction? | By passing a ray of electrons at a high voltage (e.g., 5,000 V) through a sheet of graphite, which acts as a double slit diffraction arrangement. |
| What pattern is observed on the screen when electrons pass through graphite in a diffraction experiment? | Rings formed around a central bright spot. |