Three Coplanar Parallel Straight Wires Carry Equal Currents I as Shown

question 121

Multiple Choice

Three coplanar parallel straight wires carry equal currents I as shown below.The current in the outer wires is directed to the right,and that in the middle wire is directed to the left.Each pair of wires is a distance a apart.The direction of the magnetic force on the middle wire

• A)is up out of the plane of the wires.
• B)is down into the plane of the wires.
• C)is in the plane of the wires,directed upwards.
• D)is in the plane of the wires,directed downwards
• E)cannot be defined,because there is no magnetic force on the middle wire.