A magnetic field exists in a current-carrying coil of wire

Question

Quizplus · Accepted Answer

A magnetic field exists in a current-carrying coil of wire regardless of whether or not it contains a piece of iron. The magnetic field is generated by the flow of electric current through the wire, according to Ampere's law. However, the presence of iron can increase the strength of the magnetic field, as iron is a ferromagnetic material that can become magnetized by the field. The current does not need to change for the magnetic field to exist, but a changing current can cause the magnetic field to vary in strength or direction.

A Magnetic Field Exists in a Current-Carrying Coil of Wire