Lenz's Law — Electromagnetic Induction

A magnetic dipole (bar magnet) moves through a conducting loop. The changing flux Φ = ∫B·dA induces EMF = −dΦ/dt (Faraday's law). The induced current creates a field opposing the change (Lenz's law). The braking force F ∝ v²μ²/R decelerates the magnet.