Faraday's Law

Faraday's Law of Induction

A changing magnetic flux through a coil induces an electromotive force (EMF). Michael Faraday discovered this in 1831:

mathcal{E} = N rac{DeltaPhi}{Delta t}

• N — number of turns in the coil
• $DeltaPhi$ — change in magnetic flux (Wb)
• $Delta t$ — time over which the flux changes (s)
• $mathcal{E}$ — induced voltage (volts)

Lenz's Law

The induced EMF always opposes the change that caused it (the negative sign in the full equation, mathcal{E} = -N rac{dPhi}{dt}). This is why braking electromagnets resist motion, and transformers have opposing primary and secondary currents.

Applications

Faraday's law is the operating principle of:

• Generators — rotating coil changes flux $o$ AC electricity
• Transformers — changing primary flux induces secondary EMF
• Induction cooktops — changing field induces currents in the pot

Examples

Your Task

Implement induced_emf(N, delta_phi, delta_t) returning the magnitude of the induced EMF.