Square Wires

Discussion in 'Homework Help' started by f74bat, Dec 1, 2008.

  1. f74bat

    Thread Starter Member

    Nov 26, 2008
    our long, straight wires are parallel to each other and their cross-section forms a square. Each side of the square measures 0.0112 m.


    If each wire carries a currrent of 8.33 A in the direction shown, find the magnitude of the total magnetic field at P, the center of the square.

    For this question I tried using B=(mu*I)/(2*pi*d) and multiplying the answer by 4 cuz there are 4 sides but my answer is not correct.
  2. mik3

    Senior Member

    Feb 4, 2008
    You have to assume a positive direction of current flow. Say the dot is the positive direction and the cross is the negative direction. Thus find B each wire causes at point P and then add them together. According to, the assumptions, the right-bottom wire will give a negative B and the other wires positive B.