what is different between eddy current with emf?

Answer 1

*An eddy current (also known as Foucault current) phenomenon discovered by French physicist Léon Foucault in 1851, is caused by a moving magnetic field intersecting a conductor or vice-versa. The relative motion causes a circulating flow of electrons, or current, within the conductor. These circulating eddies of current create electromagnets with magnetic fields that oppose the change in the external magnetic field (see Lenz's law). The stronger the magnetic field, or greater the electrical conductivity of the conductor, or greater the velocity of motion, the greater the currents developed and the greater the opposing force.

An analogous current is seen in water: when dragging an oar, localised areas of turbulence (known as eddies) give rise to persistent vortices.

An eddy current is a swirling current set up in a conductor in response to a changing magnetic field. By Lenz's law, the current swirls in such a way as to create a magnetic field opposing the change; to do this in a conductor, electrons swirl in a plane perpendicular to the magnetic field.
[An eddy current is a swirling current set up in a conductor in response to a changing magnetic field. By Lenz¹s law, the current swirls in such a way as to create a magnetic field opposing the change; to do this in a conductor, electrons swirl in a plane perpendicular to the magnetic field.

Because of the tendency of eddy currents to oppose, eddy currents cause energy to be lost. More accurately, eddy currents transform more useful forms of energy, such as kinetic energy, into heat, which is generally much less useful. In many applications the loss of useful energy is not particularly desirable, but there are some practical applications. One is in the brakes of some trains. During braking, the metal wheels are exposed to a magnetic field from an electromagnet, generating eddy currents in the wheels. The magnetic interaction between the applied field and the eddy currents acts to slow the wheels down. The faster the wheels are spinning, the stronger the effect, meaning that as the train slows the braking force is reduced, producing a smooth stopping motion.]

*Electromotive force (emf) is the amount of energy gained per unit charge that passes through a device in the opposite direction to the electric field existing across that device. It is measured in volts.
emf is induced when a conductor cuts magnetic field lines or when the magnetic field through a coil changes.
* you can calculate induced emf by Faraday's Law.
* If the magnetic flux in a circuit changes for any reason, then an Electric Field will be generated in the circuit - it is called an induced emf.

An emf can be produced in a circuit loop if:
* The B-field's strength varies with time,
B(t) constant.
Example: Turing on or off a magnetic field.
* The area of the circuit loop varies with time,
A(t) constant.
Example: Motional emf problems.
* The angle between B and A varies with time,
q(t) constant.
Example: Loop turning in a magnetic field.
Source(s):
http://www.ac.wwu.edu/~vawter/physicsnet...
∫½√²³×÷πΔφ£
http://en.wikipedia.org/wiki/calculus......
http://www.bugmenot.com/

Answer 2

EDDY CURRENT:
An eddy current is a phenomenon caused by a moving magnetic field intersecting a conductor or vice-versa. The relative motion causes a circulating flow of electrons or current within the conductor. These circulating eddies of current create electromagnets with magnetic fields that oppose the external magnetic field (see Lenz's law). The stronger the magnetic field, or greater the electrical conductivity of the conductor, the greater the currents developed, and the greater the opposing force.

EMF (ELECTROMOTIVE FORCE):
Electromotive force (emf) is a measure of the strength of a source of electrical energy. The unit of emf is the volt (energy per unit electric charge) and so the term 'force' is misleading.

Electromotive force 'drives' current to produce magnetic effects; eddy currents create 'disruptions' in the magnetic field resulting in wasted energy.

Answer 3

EMF (ELECTROMOTIVE FORCE):
Electromotive force (emf) is a measure of the strength of a source of electrical energy. The unit of emf is the volt.

EDDY CURRENT:
Eddy current is a type of lose in the electrical equipments in which the heat is produce for avoid this lose we ues the thin stempings of 3mm to 5mm.