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: Electric Potential Over Non-Uniform Rod

  1. Feb 15, 2015 #1
    1. The problem statement, all variables and given/known data
    The thin plastic rod shown in the figure has length L = 18.0 cm and a nonuniform linear charge density λ = cx, where c = 14.5 pC/m2. With V = 0 at infinity, find the electric potential at point P1 on the axis, at distance d = 5.10 cm from one end.

    Figure is attached.

    2. Relevant equations
    [tex]q= \lambda x \\
    \lambda = cx \\
    dv = (kdq)/r[/tex]

    3. The attempt at a solution
    [tex]q= \lambda x \\
    dq = \lambda dx \\
    dq = cxdx[/tex]

    I figured you would just use
    [tex]v =kc \int_{0}^{L}[x/(x+d)]dx[/tex]
    And plug in L, solving for V, in which I get -0.17V, which is flagged as incorrect.

    Am I approaching this correctly or is there something I am missing?

    Attached Files:

  2. jcsd
  3. Feb 15, 2015 #2


    User Avatar

    Staff: Mentor

    The setup for the integral looks okay. You'll have to show details of how you solved the integral.
  4. Feb 15, 2015 #3
    This can be closed, I just integrated incorrectly.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted