An alternating-current generator converts which form of energy into electrical energy?

An alternating-current generator is designed to convert mechanical energy into electrical energy. This process typically involves a rotating mechanical component, such as a rotor, which moves within a magnetic field. As the mechanical parts rotate, they create a change in magnetic flux that induces an electric current according to Faraday's law of electromagnetic induction.

This transformation is fundamental to the operation of many power generation systems, where mechanical energy is often produced by engines or turbines driven by sources such as fossil fuels, wind, or hydroelectric power. The generated electrical energy is in the form of alternating current (AC), which is commonly used in household and industrial power systems.

The other options reflect incorrect conversions or types of energy: electrical energy cannot be converted into electrical energy by a generator; mechanical energy transformed into direct current does not reflect the operation of an AC generator; and while electrical energy can indeed create magnetic fields, this is not the primary function of an AC generator. Therefore, recognizing the core function of the AC generator as converting mechanical energy into electrical energy is essential for understanding its role in power generation.