Glossary
EMF (Electromotive Force)
The voltage induced in a circuit due to a changing magnetic flux, representing the energy per unit charge supplied by an energy source.
Example:
In a simple circuit, the battery provides the EMF that drives the current, similar to how a changing magnetic field can induce an EMF in a wire loop.
Electromagnetic Induction
The process of generating an electromotive force (voltage) across an electrical conductor in a changing magnetic field, which can drive a current in a closed circuit.
Example:
A hydroelectric power plant uses electromagnetic induction to convert the mechanical energy of flowing water into electrical energy by spinning turbines within magnetic fields.
Faraday's Law
A fundamental law of electromagnetism stating that the magnitude of the induced electromotive force (EMF) in a circuit is directly proportional to the rate of change of magnetic flux through the circuit.
Example:
Wireless charging pads for phones work on the principle of Faraday's Law, where a changing magnetic field from the pad induces a current in the phone's coil.
Lenz's Law
A law that specifies the direction of the induced current, stating that the induced current will flow in a direction that opposes the change in magnetic flux that caused it.
Example:
When you push a north pole of a magnet into a coil, Lenz's Law dictates that the induced current will create a north pole to repel the incoming magnet, opposing its motion.
Magnetic Flux (ΦB)
A measure of the total number of magnetic field lines passing through a given area, quantifying the amount of magnetic field penetrating a surface.
Example:
If a solar flare sends a burst of magnetic energy towards Earth, the magnetic flux through a satellite's antenna could change rapidly, potentially inducing currents.
Right-Hand Rule (RHR)
A mnemonic used to determine the direction of magnetic fields, forces, or induced currents in various electromagnetic scenarios.
Example:
To determine the direction of the magnetic field inside a solenoid, you can use the Right-Hand Rule by curling your fingers in the direction of the current and your thumb will point to the north pole.