The two wires shown in the figure carry currents of I = 5.63 A in opposite directions and are separated by a distance of d0 = 8.23 cm. Calculate the net magnetic field at a point midway between the wires. Use the direction out of the page as the positive direction and into the page as the negative direction in your answer.

Question

anonymous · Answer

I got this answer now I just need help with "Calculate the net magnetic field at point P2 - that is 19.4 cm to the left of the wire on the left."

anonymous · Answer

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festinger · Answer

Both wires produce a magnetic field but are in opposite directions at point P2. This field has to be out of the page (positive in the question's convention) since the wire on the left is closer to point P2, and the wire on the left produces a out of paper field at P2. 

The formula to use is $$B=\frac{\mu_{0}I}{2\pi r}$$
Where $\mu_{0}$ is the permeability of free space, defined to be $4 \pi \times 10^{-7}$ and r is the distance of the wire to the point in question.

festinger · Answer

So the expression,
$$B(P2)=\frac{\mu_{0}*5.63}{2 \pi}(\frac{1}{0.194}-\frac{1}{0.194+0.0823})$$

anonymous · Answer

From that I got 2.72E-6 and it says its wrong :/

festinger · Answer

I got 1.729*10^-6 T.

anonymous · Answer

Oh! must have been a miscalculation! Thank you!!

anonymous · Answer

how did you get that? I cant seem to