When a current is passed back and forth through a piece of metal, what is produced?

When a current is passed back and forth through a piece of metal, it produces a magnet due to the phenomenon known as electromagnetism. When an electric current flows through a conductor, it generates a magnetic field around it. This is a fundamental principle of physics, where the movement of electrical charges creates a magnetic environment.

In the context of alternating current (AC), which is what is implied by the current being "passed back and forth," the direction of the current changes periodically. This changing current not only results in a magnetic field that also alternates in direction but can also be harnessed to create electromagnets. This is significant in various applications, including electric motors, transformers, and generators, where the interaction between electric currents and magnetic fields is essential for operation.

The other choices relate to different phenomena. Electricity itself is the flow of electrical charge and is not produced as a result of the changing current in this scenario, while heat can be generated as a secondary effect due to resistance in the metal but is not the primary outcome of the current flow in the context of generating a magnetic field. Light can be produced in certain conditions (like when electric arcs occur), but again, the direct and specific outcome of the alternating current in this case leads primarily