Net Magnetic Field of current carrying wires:

1. Sep 20, 2009

spriter

1. The problem statement, all variables and given/known data
http://img33.imageshack.us/img33/4547/walker4ech22pr054.jpg [Broken]

Two long, straight wires are oriented perpendicular to the page, as shown in the figure . The current in one wire is I-1 = 3.0 A, pointing into the page, and the current in the other wire is I-2 = 4.0 A, pointing out of the page.

Question: Find the magnitude and direction of the net magnetic field at point P.

2. Relevant equations

Equations: B = u0*I/2*pi*r - where u0 = 4*pi * 10^-7 ( T * m/A), I = current, and r = distance from wire

3. The attempt at a solution

I found the magnetic field of both the wires at point P by using the above equation and the distance for I-1 as .05 meters and distance (r) for I-2 by using Pythagorean theorem .05^2 + .05^2 = c^2, etc - came out to about .071 meters.

After finding the two magnetic fields, I see that the magnetic fields are pointing in the opposite direction at point P, so I subtract them, but that is the wrong answer for the net magnetic field.

Last edited by a moderator: May 4, 2017
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