Answer: Current produces magnetic field around a conductor.
- A A steady current produces an induced voltage across the wire
- B Current produces magnetic field around a conductor
- C A static magnetic field alone generates a current in a wire
- D Two like magnetic poles always repel each other
Correct answer: B. Current produces magnetic field around a conductor
Explanation: Oersted showed in 1820 that an electric current creates a magnetic field around the conductor: linking electricity and magnetism.
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.