How Are Cathode Rays Deflected by Current-Carrying Wires?

[randomstu1997]

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 ?

 

[berkeman]

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?

 

[randomstu1997]

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

 

[berkeman]

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?

 

[randomstu1997]

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

 

[berkeman]

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.

 

[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. This opposite reactive force pushes the electron away. Am I right?