What is Faraday's law of electromagnetic induction?

Faraday's law states that the induced EMF in a circuit equals the negative rate of change of magnetic flux through the circuit: EMF = −N dΦ/dt. The faster the flux changes (faster magnet motion, more turns, stronger field), the greater the induced voltage.

Lenz's law states that the direction of the induced current is such that it opposes the change in magnetic flux that produced it. If you push a north pole toward a coil, the induced current creates a north pole facing the magnet to repel it. This is energy conservation in action.

How does a generator work?

A generator converts mechanical energy to electrical energy by rotating a coil in a magnetic field. As the coil rotates, the magnetic flux through it changes sinusoidally, inducing an alternating EMF: EMF = NBAω sin(ωt). This is the basis of AC power generation.

Electromagnetic Induction

Explore Faraday's law of electromagnetic induction. Push a magnet through a coil or spin a generator to see how changing magnetic flux induces an EMF and current.

Induction Parameters

Mode

Presets

Speed = 5

Turns = 10

B Field = 0.50 T

0.50

Coil Area = 0.050 m²

0.050

Show

Flux arrows Induced current EMF graph

Properties

Mode	Magnet through Coil
B Field	0.50 T
Turns	10
Area	0.050 m²
Flux (Φ)	--
dΦ/dt	--
Induced EMF	--
Current Dir.	--

The Physics Behind It

Induction Formulas

Magnetic flux: Φ = BA cosθ
Faraday's law: EMF = −N dΦ/dt
Motional EMF: EMF = BLv
Generator EMF: EMF = NBAω sin(ωt)

Key Concepts

Faraday's law: a changing magnetic flux through a loop induces an EMF proportional to the rate of change
Lenz's law: the induced current opposes the change that caused it (hence the minus sign)
More turns amplify the induced EMF linearly
Generators convert mechanical rotation into alternating EMF using electromagnetic induction

Electromagnetic Induction

Induction Parameters

Properties

The Physics Behind It

Induction Formulas

Key Concepts

Related Visualizations

Magnetic Field

Circuit Builder

Derivative

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