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: Magnetic field of wire

  1. Mar 10, 2010 #1
    1. The problem statement, all variables and given/known data

    A long straight wire lies along the z-axis and carries an 8A current in the +z direction. Find the magnetic field (magnitude and direction) produced at x = 0.4m, y = 0, z = .3m by a .7mm segment of wire centered at the origin.

    2. Relevant equations

    B = u(0)I / 2piR

    3. The attempt at a solution

    b = (4(pi)x10^-7) (8A) / (2pi (.7x10^-3) ==> 2.3 mT(tesla)

    I think that's right, but I'm not sure where the magnitude and direction with the vectors come in. I'm assuming you subtract vector 1 from origin vector to leave .4i + .3k. Then do you take the magnitude and multiply it by b?

    Thanks for any help.
  2. jcsd
  3. Mar 10, 2010 #2


    User Avatar
    Homework Helper

    You didn't use the right equation to find B. B = u(0)I / 2piR is for an infinitely long wire, but the question asks for the field produced by a finite wire segment.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook