When a bulk conductor is exposed to a changing magnetic flux, circulating currents (eddy currents) are induced throughout its volume. Effects: (1) Heating — used in induction furnaces and induction cooktops. (2) Electromagnetic braking — opposing the motion of the conductor (used in magnetic braking of trains). (3) Electromagnetic damping — galvanometers with metal frames are dead-beat (quickly reach equilibrium). Reducing eddy currents: use laminated cores (thin insulated sheets stacked together), increasing resistance to circulating paths. Eddy currents always follow Lenz's law.