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: Uniformly Charged Circular Disk

  1. Oct 11, 2012 #1
    1. The problem statement, all variables and given/known data
    In what direction (using cylindrical coordinates) around a uniformly disk does the electric field NOT point?

    2. Relevant equations
    The directions could be r, θ, or z.

    3. The attempt at a solution
    I don't think it can point in the θ or the z direction-- either one would imply that there is a built-in preference to space for a certain direction, because symmetry arguments say that these two directions should be treated equally in all directions.

    I'm not sure though-- I'm assuming they mean around the edge of the disk on the outside, is this correct?
  2. jcsd
  3. Oct 12, 2012 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Hello cheungw. Welcome to PF !

    What if they don't mean around the edge of the disk ?

    What if they mean in the vicinity of the disk ?
  4. Oct 12, 2012 #3
    The problem says "around" the disk, so that probably means where does E not point outside of the disk.

    to answer, consider the electric field in regions far far away from the disk, so that the disk appears to be a point. What would the field look like?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook