Eddy currents are circulating loops of electric current that are induced in conductors when they are exposed to a changing magnetic field.They are applied in induction heating (used in cooking and metalworking), electromagnetic braking systems (in trains and roller coasters), and non-destructive testing (to detect flaws in metal structures).However, they can also cause unwanted energy loss in electrical transformers and motors, which is why laminated cores are often used to minimize their effect.In real life, eddy currents are both useful and important.