Electron guns and beams

[joker_900]

Hey guys

Apparently I have to know how to find the energy of accelerated electron beams for a test, and I'm not sure how. Any help?

I'm assuming it's talking about electron guns: I think this consists of a heated cathode which emits electrons via thermionic emission, and an anode which accelerates them. But how do you actually get the cathode and anode (i.e. what are the circuits and how does one make each electrode charged). Is the electron beam energy just the voltage between the cathode and anode multiplied by Q (=It)?

Thanks, Jonty

[Hootenanny]

I'll give you a big clue and say that the definition of potential difference (or voltage) is work done per unit charge. The circuitry does not matter in the slightest, there's only one thing you need to know about the electrodes.