The figure shows three long,parallel,current-carrying wires.The current directions are indicated for currents I₁ and I₃.The arrow labeled F represents the net magnetic force acting on current I₃.The three currents have equal magnitudes.What is the direction of the current I₂? A) into the picture (in the direction opposite to that of I₁ and I₃) B) horizontal to the right C) vertically upward D) vertically downward E) out of the picture (in the same direction as I₁ and I₃)

Question

Quizplus · Accepted Answer

The net magnetic force F is directed towards the right, therefore the magnetic fields produced by the currents I₁ and I₃ are in opposite directions. Since the currents in all three wires have the same magnitude, the magnetic field produced by the current in I₂ must be equal in magnitude but opposite in direction to the magnetic field produced by the current in I₁. Therefore, the direction of the current in I₂ must also be opposite to that of I₁ and I₃, which means it is into the picture.

The Figure Shows Three Long,parallel,current-Carrying Wires