Question

The currents in three parallel wires, X, Y, and Z, each have magnitude I and are in the directions shown. Wire y is closer to wire X than to wire z. The magnetic force on wire y is

(A) zero

(B) into the page

(C) out of the page

(D) toward the bottom of the page

(E) toward the left

Answer 1

The correct option is: (E) toward the left

Explanation:

Each wire creates a magnetic field around itself. Since all the currents are the same, and wire Y is closer to wire X, wire X’* field will be stronger there and dominate the force on wire Y. So we can essentially ignore wire Z to determine the direction of the force. Since X and Y are in the same direction they attract and Y gets pulled to the left.