The figure shows two long wires carrying equal currents I₁ and I₂ flowing in opposite directions.Which of the arrows labeled A through D correctly represents the direction of the magnetic field due to the wires at a point located at an equal distance d from each wire? A)A B)B C)C D)D E)The magnetic field is zero at that point.

Question

Quizplus · Accepted Answer

The magnetic field due to each wire is perpendicular to the plane formed by the two wires, and is also perpendicular to the line connecting the point of interest with the wire. Thus, the magnetic field due to each wire at the point of interest will be into the plane of the figure for one wire and out of the plane of the figure for the other wire. The field vectors will be equal in magnitude and opposite in direction, so they will cancel out along the line connecting the wires. The only remaining component of the magnetic field will be perpendicular to the line connecting the wires, and will point in the direction shown by arrow B.

The Figure Shows Two Long Wires Carrying Equal Currents I1

The Figure Shows Two Long Wires Carrying Equal Currents I₁