What is produced by passing electric current through a conductor, which acts like a magnet?

Passing an electric current through a conductor creates a magnetic field around it, which is the fundamental principle behind electromagnets. This phenomenon is described by Ampère's circuital law, which states that electric currents generate a magnetic field. In the case of a solenoid—a coil of wire through which current flows—the magnetic field can be concentrated and controlled, resulting in a magnetic field that can be turned on or off based on the flow of electricity.

Electromagnets are widely used in various applications, such as in electric motors, magnetic locks, and MRI machines, due to their ability to easily vary the strength of the magnet by adjusting the current. This versatility makes them essential in both industrial and technological settings.

While other devices like inductors and transformers are related to electricity and magnetism, they operate based on different principles. Inductors store energy in a magnetic field when electrical current passes and do not function as magnets in the same way electromagnets do. Transformers transfer electrical energy between two circuits through electromagnetic induction, rather than acting as a transient magnet as electromagnets do. Piezoelectric devices convert mechanical stress into electrical charge, which is unrelated to magnetism created by electric current.