What is produced whenever a conductor carries a current?

• A. Electric field
• B. Magnetic field
• C. EMF radiation
• D. Electrical potential

Answer: (C)

Whenever charges move through a conductor, they generate a magnetic field that encircles the path of the current. This magnetic field arises from moving charges and is described by Ampere’s law. In a steady (DC) current, the magnetic field is constant in time, though it does not mean there’s no electric field inside the conductor—the electric field drives the current, and a related electrical potential exists. Electromagnetic radiation would occur only if the current changes with time (such as with AC or pulsed currents), producing changing fields that radiate away. So the feature produced around a current-carrying conductor is a magnetic field; radiation would come only from time-varying currents.