What is generated when a changing electric current is passed back and forth through metal?

When a changing electric current flows back and forth through metal, it generates a magnetic field. This phenomenon is a direct consequence of electromagnetism, which is described by Maxwell's equations. When the electric current changes, it creates a varying magnetic field around the conductor. This principle is employed in various applications, such as transformers and inductors, where alternating currents are used to induce magnetic fields that can influence other electrical components within a circuit.

In contrast, an electric field refers to the area around charged particles that exerts a force on other charged objects but does not directly result from a changing current in the same way. A thermal field would relate to temperature variations within a material, not directly linked to the principles of changing electric currents and their associated fields. Lastly, a static field refers to a field that is created by stationary charges rather than by the dynamic process of current fluctuations. Thus, the magnetic field generated by changing currents is a fundamental concept in understanding electromagnetism and its applications.