Faraday Calculator

Faraday's Law of Induction

When magnetic flux through a coil changes, an electromotive force (EMF) is induced in the circuit. Faraday's law quantifies this effect and is the basis for generators, transformers, and many sensors.

Faraday's Law Formula

$$\varepsilon = -N \frac{d\Phi}{dt}$$

Magnetic flux through a coil is:

$$\Phi = B \cdot A$$

Where $N$ is the number of turns, $B$ is magnetic field in teslas, and $A$ is cross-sectional area. The negative sign reflects Lenz's law: induced current opposes the flux change.

Frequently Asked Questions

What causes induced EMF?

A changing magnetic flux through a coil induces voltage. This can result from changing magnetic field strength, coil area, or orientation relative to the field.

Why is the EMF negative?

Lenz's law states the induced current creates a magnetic field opposing the original flux change. The minus sign in Faraday's law encodes this direction.

How do coil turns affect EMF?

EMF is directly proportional to the number of turns. Doubling turns doubles the induced voltage for the same flux change rate.

What units are used?

Magnetic field is in teslas (T), area in square meters or square centimeters, time in seconds, and induced EMF in volts (V). Flux is measured in webers (Wb).

Where is Faraday's law used?

Electric generators, induction motors, transformers, wireless charging, and magnetic field sensors all rely on electromagnetic induction described by Faraday's law.

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Faraday's Law of Induction

Faraday's Law Formula

Frequently Asked Questions

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