1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Electrostatic potential on the surface of a conductor

  1. Dec 23, 2011 #1
    1. The problem statement, all variables and given/known data

    At the surface of a conductor the potential is constant .. I cant get my head around this ..

    2. Relevant equations
    E=-grad V

    3. The attempt at a solution

    The only reason I can think about this is Electric field is perpendicular at the surface , hence no work is done when moving a point charge around the surface , hence potential is constant ..

    But if V is constant , the surely E=-grad (V)-> E=0 , which is not the case since there are charges on the surface of the conductor, so surely must provide a E field normal to the surface ..

    Thanks for any help
    Last edited: Dec 23, 2011
  2. jcsd
  3. Dec 23, 2011 #2
    Noone ? Does noone understand what I am saying or does noone know the anwer?
  4. Dec 23, 2011 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    Say the surface lies in the xy-plane, for example. You'd have V(x,y,0)=V0 so that ∂V/∂x=∂V/∂y=0, but that doesn't imply that ∂V/∂z=0.
  5. Dec 23, 2011 #4
    Cheers :D
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook