Electromagnetic induction facts for kids
|Electricity · Magnetism|
When a coiled wire is introduced near a magnet, the magnetic lines of force pass through the coil. This causes the magnetic flux to change. Magnetic flux is represented by the symbol , therefore we can say that = BAcos(a) and the resulting unit will be , where T is the unit for magnetic field and is the unit for area.
Michael Faraday found that an electromotive force is generated when there is a change in magnetic flux in a conductor.
His laws state that:
is the electromotive force, measured in volts;
is the change in magnetic flux, measured in webers;
is the change in time, measured in seconds.
In the case of a solenoid:
N is the number of loops in the solenoid.
The negative sign in both equation above is a result of Lenz's law, named after Heinrich Lenz. His law states that the electromotive force (EMF) produces a current that opposes the motion of the changing magnetic flux.
Images for kids
Faraday's experiment showing induction between coils of wire: The liquid battery (right) provides a current that flows through the small coil (A), creating a magnetic field. When the coils are stationary, no current is induced. But when the small coil is moved in or out of the large coil (B), the magnetic flux through the large coil changes, inducing a current which is detected by the galvanometer (G).
Electromagnetic induction Facts for Kids. Kiddle Encyclopedia.