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The wire in the figure below carries a current of 10 A. Suppose that a second lo

ID: 2142560 • Letter: T

Question

The wire in the figure below carries a current of 10 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 31 A. Use Amp

The wire in the figure below carries a current of 10 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 31 A. Use Ampere's law to find the magnitude of the magnetic field at a distance of r = 0.72 from the wires when the currents are in the same and in opposite directions.

Explanation / Answer

The magnetic field looping around an infinite wire is:
B = mu0 I / (2 pi r)

If they are going the same direction, add the currents to get I. If they are going the opposite direction, take the difference. They give you r. Look up the permeability of free space mu0. Plugnchug.