Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electric potential, hollow metalic cylinder

  1. Nov 27, 2011 #1
    A hollow metalic cylinder of radius r and lenght l, has potential V0 over its surface. The axis of the cylinder coincides with the z axis, and the cylinder is centered at the origin. The cylinder is placed paralel(the electric field paralel with z axis) to an otherwise uniform electric field E.
    I need the variation of electric potential V with z axis.
  2. jcsd
  3. Nov 28, 2011 #2

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The potential inside such a cavity would be a constant V_0.
  4. Nov 28, 2011 #3
    Why are you saying that it's constant V_0? The cylinder is not closed as far as I understand. It's like a toilet paper roll. If it were closed with lids, I'd see why, but in this case how would you explain?

    The boundary conditions are V_0 on the roll, and V_1 in one side, and V_2 in the other, such that (V_2-V_1)/l = E. If V_1 = V_2 = V_0 as you say, this means that E = 0, which is the trivial case.
  5. Nov 30, 2011 #4
    This is not perfectly valid, because it depends on the permitivity of the cylinder. According to Faraday a metall would shield away every electric field. But if you plot the field, you will see, that the field gets into the hollow space.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook