What is described by the principle of electromagnetic induction?

The principle of electromagnetic induction refers to the process where a changing magnetic field induces an electromotive force (EMF) in a conductor. This phenomenon was discovered by Michael Faraday and is fundamental to the operation of many electrical devices, including generators and transformers. In essence, when a conductor moves through a magnetic field or when a magnetic field around a conductor changes, an electrical current is generated within that conductor.

This principle is vital for various applications in electrical engineering and physics, as it explains how electrical energy can be generated from mechanical movement or changes in magnetic fields. The correct answer highlights the fundamental relationship between electrical energy and magnetic fields, emphasizing the role that magnetic fields play in the transfer of electrical energy.

The other choices are related to different electrical concepts but do not accurately represent electromagnetic induction. The first option highlights energy transfer via resistors, which doesn't involve magnetic fields. The third option discusses the conversion of electrical energy to thermal energy, an entirely different process commonly observed in resistive heating. Finally, the storage of electrical energy in batteries involves chemical reactions rather than electromagnetic induction.