1. Not finding help here? Sign up for a free 30min 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!

Ring of radius R and uniform charge

  1. May 17, 2012 #1
    1. The problem statement, all variables and given/known data
    At what distance along the central axis of a ring of radius R = 0.200 m and uniform charge is the magnitude of the electric field due to the ring's charge maximum? What is the positive solution for z?


    2. Relevant equations
    E = [itex]\frac{kqz}{(z^2+R^2)^(3/2)}[/itex]



    3. The attempt at a solution
    I know I should differentiate that above equation with respect to z and then set it equal to 0 to get z but i just dont know how to differentiate that ..

    E = [itex]\frac{kqz}{(z^2+R^2)^(3/2)}[/itex]

    the k and the q are held as constants and can be taken out of the differentiation ..

    = kq*[[itex]\frac{d}{dz}[/itex]((z2+R2)3/2]

    isn't [itex]\frac{d}{dz}[/itex]((z2+R2)3/2 = -3z(z2+R2)^(-5/2) ??

    so it would be kq [-3z(z2+R2)^(-5/2)]

    but that doesn't work for when you set it = 0. what am i supposed to be doing that im not
     
  2. jcsd
  3. May 17, 2012 #2
    never mind .. i got it now!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Ring of radius R and uniform charge
Loading...