What term describes the phenomenon when current flows through a conductor and a magnetic field forms around it?

• A. Electromagnetism
• B. Induction
• C. Capacitance
• D. Resistance

Answer: (A)

Electric current flowing through a conductor generates a magnetic field around the conductor, which is a hallmark of electromagnetism. This field forms circular lines around the wire and its strength follows the amount of current (and can change if the current changes). The idea here is the direct relationship between moving charges and magnetic fields, a core part of electromagnetism.

Induction would involve producing a voltage by changing magnetic flux, which is a different situation from simply having a current produce a magnetic field. Capacitance deals with storing energy in an electric field between conductors, and resistance describes opposition to current flow. So the best term for the described phenomenon is electromagnetism.