How does electromagnetic induction work?
Electromagnetic induction produces an electromotive force when magnetic flux changes. Generators and transformers use this principle. The mere presence of a magnet is insufficient; the relevant flux must change over time.
Faraday's and Lenz's laws
Magnetic flux depends on field strength, surface area, and orientation. Rotating a coil, moving a magnet, or changing field strength can induce an electromotive force. Faraday's law relates voltage to the rate of flux change. Lenz's law specifies a response opposing the change, consistent with energy conservation. Without a closed circuit, a voltage can exist without a sustained current.
Energy conversion and uses
A generator converts mechanical work into electrical energy rather than creating energy from nothing. A transformer changes alternating-voltage levels through a shared changing magnetic field; steady direct current cannot provide its normal operation. Induction cooktops heat conductive cookware through induced currents. Resistance, eddy currents, and magnetic-core losses limit the efficiency of real devices.