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

Confusion: Van de Graaff generator

  1. Dec 3, 2011 #1
    My physics book explains a van de Graaff in this way:

    A small conducting sphere of radius a and carrying charge q is located inside a larger shell of radius b that carries charge Q. A conducting path is momentarily established between the two conductors, and the charge q then moves entirely to the outer conductor, because the charge on a conductor always moves to its outer surface.

    But in any actual machine, you'd have to punch a hole in the outer sphere to bring the charge inside; wouldn't that merge the inner and outer surfaces? You can't even apply Gauss' Law like usual because the Gaussian surface would have to pass through the hole, and there'd be a nonzero field there.

    Am I just completely misunderstanding it?

    Edit: In addition, since the potential of the outer shell is so big (and should be uniform throughout), why doesn't charge flow off it onto the belt?
     
    Last edited: Dec 3, 2011
  2. jcsd
  3. Dec 3, 2011 #2

    clem

    User Avatar
    Science Advisor

    The hole is small enough that its influence is negligible.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Confusion: Van de Graaff generator
  1. Van de graaff (Replies: 1)

  2. Van de graaff (Replies: 1)

Loading...