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!

Please help with this electric potential problem

  1. May 2, 2009 #1
    1. The problem statement, all variables and given/known data

    One conductor of an overhead electric transmission line is a long aluminum wire 2.40 cm in radius. Suppose that at a particular moment it carries charge per length 1.40 µC/m and is at potential 350 kV. Find the potential 10.9 m below the wire. Ignore the other conductors of the transmission line and assume the electric field is everywhere purely radial.

    2. Relevant equations

    i think for this problem you would use the integral of dq/r right?

    3. The attempt at a solution

    i am not sure how to do this problem. it tells me that it is 10.9 m below the line but it doesn't say where under the wire. would i some how use the 350 kV and get the location under the wire? also i am not sure how the radius of the wire comes in the equation. the ones that i have been doing are rods that have no radius so i am not really sure how to do this problem
     
  2. jcsd
  3. May 3, 2009 #2

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Does your textbook or course notes discuss the electric field of a line charge? That would be relevant here.
     
  4. May 3, 2009 #3
    yes but the example that they gave is much simpler and it is just a rod with no radius
     
  5. May 3, 2009 #4

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Okay, good.

    The same expression for electric field will be true here, as long as:
    • The distance is taken to the center axis of the transmission line
    • The distance is larger than the radius of the transmission line
    (Inside the transmission line, E=0 as for any conductor)
     
  6. May 3, 2009 #5
    oh sorry this is asking for electrical potential though
     
  7. May 3, 2009 #6

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Potential and electric field are related via doing an integral.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Please help with this electric potential problem
Loading...