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Electromagnetic Induction

Faraday's Law: ε = −N · dΦ/dt — changing flux induces EMF

Electromagnetism Faraday's Law Lenz's Law Magnetic Flux

Magnet Speed 1.0× Field Strength 1.0 T Coil Turns N = 10

Φ = 0.000 Wb ε = 0.00 V I = 0.00 mA F_Lenz = 0.00 mN

Faraday's Law of Electromagnetic Induction

When magnetic flux through a coil changes, an EMF is induced: ε = −N · dΦ/dt where N is the number of turns and Φ = B·A·cosθ is the magnetic flux. The negative sign reflects Lenz's Law — the induced current creates a magnetic field opposing the change in flux.

Bar Magnet mode: Drag the magnet toward/away from the coil. The galvanometer deflects left (approaching N-pole) or right (receding N-pole).
Rotating Coil: Coil spins in a uniform field — flux varies as Φ = B·A·cos(ωt), giving ε = NBAω·sin(ωt).
AC Generator: See how mechanical rotation produces alternating current.