SACE Stage 2 Physics — Electricity & Magnetism 2.5

Eddy Currents & Magnetic Braking

Drop a conducting plate through a magnet's gap and the changing flux induces swirling eddy currents. By Lenz's law those currents feel a force that opposes the motion — the plate brakes. Compare two plates side-by-side, slot one to break the current loops, or sweep a coin over a metal-detector coil and watch the signal spike.