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Artificial Magnetic Fields – Electromagnetism (Grade 12) -- CRT e-beam deflection

  1. Dec 16, 2014 #1
    1. The problem statement, all variables and given/known data
    A cathode-ray tube aims electrons parallel to a nearby wire that carries current in the same direction. What will happen to the cathode rays in terms of deflection?

    3. The attempt at a solution
    The Motor force deflects the cathode rays ?
    upload_2014-12-16_20-32-35.png
     
  2. jcsd
  3. Dec 16, 2014 #2

    berkeman

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    Staff: Mentor

    Your picture doesn't match the question (coil versus parallel wire). Can you please check that?
     
  4. Dec 16, 2014 #3
    Sorry. Then lets say a steady beam of electrons move parallel to the wire carrying current. Then what happens? Thanks
     
  5. Dec 16, 2014 #4

    berkeman

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    Staff: Mentor

    Yeah, that matches your problem statement better. :-)

    So what do you think? Think about the right hand rule -- what does the B-field look like around the wire? And again use the right hand rule to figure out the Lorentz force on the e-beam from that B-field. Are you familiar with the vector force equation Lorentz force?
     
  6. Dec 16, 2014 #5
    The B-field meets 90 degrees to the electron. I am not familiar with lorentz force.
     
  7. Dec 16, 2014 #6

    berkeman

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    Staff: Mentor

    Well, you need to understand the Lorentz force to answer this question. Please re-check your textbook or use a Google or Wikipedia search. Please let us know what you find.
     
  8. Dec 16, 2014 #7
    Ok I think I got it. According to wikipedia, there must be an opposite reactive force to the force produced by lorentz equation[PLAIN]http://upload.wikimedia.org/math/1/1/7/117693a4a6d55502f66788d04f156c72.png. [Broken] This opposite reactive force pushes the electron away. Am I right?
     
    Last edited by a moderator: May 7, 2017
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