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Faraday's Law of Induction

Also known as electromagnetic induction · induced EMF

ε=NΔΦΔt\varepsilon = N \frac{\Delta\Phi}{\Delta t}

Worked example: 500 turns, 2 mWb in 0.1 s → emf = 10 V — press Try an example to run it live, then adjust anything.

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The changing flux →

Grade 12Grade 12 Physics

Flux and Faraday →

UniversityCircuits & Electrical Power

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Faraday's Law of Induction explained

εΔΦΔtN

Faraday's 1831 discovery is the bridge between mechanics and electricity: change the flux through a coil and a voltage appears, one volt per weber-per-second per turn. The N multiplies because each turn is a voltage source in series — the reason transformers and generators are wound with hundreds of turns. Sweep a magnet that changes flux by 2 mWb through a 500-turn coil in 0.1 s and you induce 10 V.

The full law carries a minus sign (Lenz's law): the induced current always opposes the change that created it — nature's built-in inertia against flux change, and the origin of eddy-current braking.

Faraday's Law of Induction formula

ε=NΔΦΔt\varepsilon = N \frac{\Delta\Phi}{\Delta t}
Where
  • ε\varepsilon= Induced EMF (V)
  • NN= Number of turns
  • ΔΦ\Delta\Phi= Flux change (Wb)
  • Δt\Delta t= Time interval (s)

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