Long straight power lines carrying an AC current of 225 A (rms) pass over a whea

Question

Long straight power lines carrying an AC current of 225 A (rms) pass over a wheat field; then end-on view is shown in the diagram. The currents are oppositely directed at any instant of time. A). How large is the peak current through the wires? B). At the instant when the current peaks, how large is the magnetic field magnitude produced by just one wire, at the point P in the wheat field below the wires? C). Using information and the diagram from the previous page, what is the net magnetic field vector (give magnitude and direction) at point P, as produced by both wires acting together when the current peaks?

Explanation / Answer

Figure not given

So assumed d = 15 m vertical and d = 3m horizontal.

a) Peak Current = sqrt(2)*Irms = sqrt(2)*225 = 318.2 A

b) B = u*I/2Pi*R

Here R = distance of point P from the wire

       = 4Pi*10^-7*I / 2Pi*R

       = (2*10^-7)*318.2 / 15

      = 4.24*10^-6 T

(c) 1.68*10^-6 T

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