Electric field, magnetic flux , potetial difference

  • Thread starter oportunity
  • Start date
  • #1

Homework Statement


As shown in the figure below, potential difference V exists between two parallel plates(a,b) that have a small hole. Uniform electric field E and magnetic flux density B exist in the region above the plates, and are perpendicular to each other. The directionof E is parallel to this page and plate b. The directionof B is perpendicular to this page from back to front. A positiely charged particle of charged q and mass m, initially at res in the hole of plate a, is accelerated by potential difference V so that it enters te region above the plate perpendiculary to E and B and travels straight through the region.
http://imageshack.us/photo/my-images/442/imagenq4.png/
http://imageshack.us/photo/my-images/442/imagenq4.png/

What is the ratio E/B?


Thanks

Please tell me how i put images in the post.
 
Last edited:

Answers and Replies

  • #2
Simon Bridge
Science Advisor
Homework Helper
17,857
1,655
Great - so where did you get stuck?
Do you know the equation that relates the force on a charged particle due to electric and magnetic fields?
Do you know how to relate the kinetic energy a charge gains when it falls through a potential difference of V?
 
  • #3
you mean lorentz force?
 
  • #4
No, i dont know. please tell me.

this is really important. help please.
 
  • #5
Simon Bridge
Science Advisor
Homework Helper
17,857
1,655
Are you not doing a course in elecromagnetism that you have notes for? Go read them?

The voltage is the electric potential energy per unit charge ... when the charge travels between the plates, then, it loses potential energy [itex]qV[/itex] and gains kinetic energy - what's the equation? You can do this.

The electric field strength is the force per unit charge ... so [itex]\vec{F}_E = q\vec{E}[/itex]

For the magnetic field, only moving charges experience a force: [itex]\vec{F}_B = r(\vec{v} \times \vec{B})[/itex]

Do you know how to evaluate a cross product? (Hint - v and B are at right angles: it's the right-hand slap rule.)

Now all you need is Newton's Laws.
 
  • #6
i get it, thanks a lot.
 

Related Threads on Electric field, magnetic flux , potetial difference

Replies
2
Views
5K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
1
Views
1K
Replies
3
Views
1K
Replies
3
Views
2K
Replies
1
Views
974
Replies
13
Views
2K
Replies
15
Views
4K
Replies
5
Views
5K
Top