Final answer:
Eddy current refers to a current loop induced in a conductor by a motional emf. It can create significant drag, known as magnetic damping, and is used in applications such as metal detectors, braking systems, and induction cooktops.
Step-by-step explanation:
Eddy current refers to a current loop that is induced in a conductor due to a motional electromotive force (emf). When a conductor moves in a magnetic field or when a magnetic field moves relative to a conductor, eddy currents are created. These currents can generate significant drag, called magnetic damping, on the motion involved.
An example of an application of eddy currents is in metal detectors, where a primary coil carrying an alternating current induces a current in a secondary coil. When a piece of metal is close to the detector, an eddy current is induced, which causes a change in the induced current within the secondary coil, triggering a signal.
Eddy currents are also used in braking systems for trains and roller coasters, as well as in induction cooktops.