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

  • #1

Homework Statement


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?

The Attempt at a Solution


[/B]The Motor force deflects the cathode rays ?
upload_2014-12-16_20-32-35.png
 

Answers and Replies

  • #2
berkeman
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Homework Statement


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?

The Attempt at a Solution


The Motor force deflects the cathode rays ?
View attachment 76670
Your picture doesn't match the question (coil versus parallel wire). Can you please check that?
 
  • #3
Sorry. Then lets say a steady beam of electrons move parallel to the wire carrying current. Then what happens? Thanks
 
  • #4
berkeman
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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?
 
  • #5
The B-field meets 90 degrees to the electron. I am not familiar with lorentz force.
 
  • #6
berkeman
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The B-field meets 90 degrees to the electron. I am not familiar with lorentz force.
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.
 
  • #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?
 
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