English subtitles

← 08ps-03 Parallel Plates Timing

Get Embed Code
1 Language

Showing Revision 1 created 10/27/2012 by Amara Bot.

  1. For the next few problems, we're going to be working with what's called
  2. a parallel plate capacitor and that's a fancy name but what it really means
  3. is that we have two plates here.
  4. One on each side here, and we give the left plate a strong positive charge +Q
  5. and we give the right plate a strong negative charge -Q.
  6. And this difference in charges gives rise to an electric field between the two plates.
  7. And I've shown this electric field using field lines here in red.
  8. And what's particularly awesome about the electric field between two parallel plates
  9. is that it's actually constant.
  10. The electric field here is just as strong as the electric field
  11. here and here and here and here.
  12. Now it's not completely constant around the edges. We get some bending.
  13. But we're just going to stick to the middle of the plates where the field is constant
  14. and ignore these edge effects.
  15. Now let's imagine that I put a proton here right next to this left plate.
  16. Now since the proton has a positive charge
  17. it should follow along the field lines and move in this direction.
  18. And since this field is constant, this proton should move with a constant acceleration.
  19. All right. Now can you tell me if the separation between the two plates is d,
  20. how long will it take this proton to move from this side of the parallel plate over to this side?
  21. Here's some values you'll need to solve the problem.
  22. The electric field strength is 1000 N/C. The plate separation is 1 cm.
  23. And here's the mass of the proton and the charge of the proton.
  24. You can put your answer down here and give your answer in nanoseconds,
  25. which corresponds to 10⁻⁹ normal seconds--good luck.