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How do you obtain electrons and know their average velocity?

  1. Mar 11, 2013 #1
    How do you obtain electrons and know their average velocity??

    Hello guys! I am currently trying to experiment with charge accelerators. I soon tripped inside a really big hole. I soon realized that I didn't know how to measure the amount of charge(in coulombs) a charged conductor has. So instead of using charged objects, I decided to use electrons. How would I go about obtaining electrons? Most importantly, how could I measure the average velocity of a beam of the electrons I obtained (if I am able to obtain them).
  2. jcsd
  3. Mar 12, 2013 #2


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    Staff: Mentor

    I am quite sure that there is a deeper problem in the whole setup...
    To get the electron velocity, you can shoot them into a magnetic or electric field and measure the curvature/deflection. Alternatively, keep track of the accelerating voltage, and calculate the velocity based on that.
  4. Mar 12, 2013 #3
    Hi guys! Yes, I thought about that last night. I decided to use a velocity selector and a hot cathode electron emitter with a low work function. The velocity selector will only allow the electrons with the desired velocity pass through the magnetic and electric fields. Provided that I apply enough energy to the hot cathode. Thanks!:smile:
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