Magnet Dropped Through a Coil Simulation

Drop a bar magnet through a ring or a coil and record the EMF: you get two pulses of opposite sign, one as the magnet enters and one as it leaves. This simulation computes the flux of the magnet's dipole field through every turn of the coil as the magnet falls under gravity, and plots ε = −N dΦ/dt in real time.

The pulses are not mirror images. By the time the magnet leaves it is moving faster, so the exit pulse is taller and narrower — yet both enclose the same area, because the flux starts and ends at zero. Flip the magnet and both pulses flip, as Lenz's law requires. Close the circuit with a low resistance and the induced current brakes the fall: the energy appears as heat in the coil.