Induced EMF and Current An induced electromotive force (EMF) is a voltage generated in a conductor when a magnetic field is changed. This happens when th...
An induced electromotive force (EMF) is a voltage generated in a conductor when a magnetic field is changed. This happens when the conductor itself is moving through the magnetic field, or when the magnetic field is changing around the conductor.
The induced EMF is equal to the rate of change of the magnetic flux (the amount of magnetic field passing through a given area) times the area itself. In other words:
EMF = -(dΦ/dt)A
where:
EMF is the induced EMF in volts
dΦ/dt is the rate of change of the magnetic flux in volts per second
A is the area of the conductor in square meters
Induced current is the electric current that flows in the conductor when an EMF is applied. The direction of the current is determined by the direction of the magnetic field and the direction of the motion of the conductor.
Examples:
When a conductor is moved through a magnetic field, an induced EMF is induced. The direction of the induced EMF is determined by the direction of the magnetic field and the direction of the motion of the conductor.
When a conductor is placed in a changing magnetic field, an induced current is induced. The direction of the induced current is determined by the direction of the magnetic field and the direction of the motion of the conductor.
A transformer is an example of an induced EMF and current. When a current is induced in a transformer coil, an EMF is induced in the second coil. This induced EMF causes the second coil to conduct current, which can be used to power devices.
Key points:
An induced EMF is always opposing to the change in magnetic flux.
An induced current is always flowing in the direction of the magnetic field.
The magnitude of the induced EMF and current is determined by the strength of the magnetic field, the area of the conductor, and the rate of change of the magnetic field