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

1. Dec 16, 2014

### randomstu1997

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 ?

2. Dec 16, 2014

### Staff: Mentor

Your picture doesn't match the question (coil versus parallel wire). Can you please check that?

3. Dec 16, 2014

### randomstu1997

Sorry. Then lets say a steady beam of electrons move parallel to the wire carrying current. Then what happens? Thanks

4. Dec 16, 2014

### 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?

5. Dec 16, 2014

### randomstu1997

The B-field meets 90 degrees to the electron. I am not familiar with lorentz force.

6. Dec 16, 2014

### 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.

7. Dec 16, 2014

### randomstu1997

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