Which device operates on the principle of electromagnetic induction?

• A. Electric heater
• B. Electric motor
• C. Electric generator
• D. Battery charger

Answer: (C)

Electromagnetic induction is the process by which a changing magnetic field within a coil of wire induces an electromotive force (EMF) in that coil. This principle is fundamental to the operation of electric generators, which convert mechanical energy into electrical energy by rotating a coil within a magnetic field or vice versa.

In electric generators, the movement of the coil through the magnetic field generates an induced current, which is a direct application of Faraday's law of electromagnetic induction. As the coil rotates, it cuts through the magnetic field lines, resulting in a flow of electricity. Thus, the operation of an electric generator is rooted in the principle of electromagnetic induction, making it the correct answer to this question.

While devices like electric heaters and battery chargers do involve the flow of electricity and can interact with magnetic fields, they do not primarily operate on the principle of electromagnetic induction. Electric motors, on the other hand, convert electrical energy into mechanical energy and utilize magnetic fields but do so through the interaction of current and magnetism rather than induction.