If the direction of the current flow changes, what else will change?

• A. The amount of resistance in the circuit
• B. The amount of voltage at the source
• C. The direction of the conductor passing through the flux lines
• D. The magnetic field of the electrons

Answer: (C)

The key idea is that the magnetic field around a conductor is determined by the direction of the current. Using the right-hand rule, if you point your thumb in the current direction, the curled fingers show the direction of the magnetic flux encircling the wire. When the current direction reverses, that curling reverses, so the magnetic flux lines around the conductor flip direction. That change in the magnetic field’s orientation is what changes. The resistance and the source voltage aren’t inherently altered by flipping current direction in a simple circuit, since they depend on the material and the source, not on the sign of the current. So the magnetic flux pattern around the conductor changes direction with the current.