A student is performing an investigation in which she wraps a current-carrying wire around an iron rod. She places the north pole of a bar magnet near the top of the rod. The magnet moves away from the rod. The student claims that a field exists between the rod and the magnet.

Question

Which argument best supports her claim?
• A. The current in the wire has created a magnetic field with its north pole at the top of the rod.
• B. The current in the wire has created a magnetic field with its south pole at the top of the rod.
• C. The current in the wire has created a gravitational field with its north pole at the top of the rod.
• D. The current in the wire has created a gravitational field with its south pole at the top of the rod.

Answer 1

The best argument to support the student's claim is option A. The current in the wire creates a magnetic field around it, and right-hand rule states that the magnetic field produced by a current-carrying wire will have its north pole pointing in the direction of the magnetic field lines around the wire. Thus, the magnetic field produced by the current in the wire has its north pole at the top of the rod.