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Induced EMF
Induced EMF is also known by some other terms like – induced electromotive force, electromagnetic induction, and electromotive force induction.
It can be termed as the production of a potential difference in a coil due to the changes in the magnetic flux through it. In simpler terms, Electromotive Force or EMF is said to be produced when the magnetic flux associated with a conductor or coil changes.
In general, the Magnetic flux is linked with the surface area when it is exposed to the magnetic field. When the magnetic field is perpendicular to the surface area, the magnetic flux is more. On the other hand, the magnetic flux is less when the magnetic field is parallel to the surface area.
What is induced Current?
It can be termed as the current produced due to changing magnetic fields in a conducting loop. E.g., generator-induced current represents a flow of charge carriers in a conductor due to the presence of an altering magnetic field.
How Does Induced EMF Implied In Producing Current and Working Mechanism
Faraday Law’s apparatus
The apparatus that is used in this law to see how a magnetic field can induce current consists of a battery, coil, switch, and galvanometer. When the switch is closed, a magnetic field is produced at the top of the coil, which is then transferred to the bottom of the coil. The galvanometer is a device used to find the current that is present in the coil. When observed that the switch is closed, the current in one direction is produced, and when the switch is opened, a current in the opposite direction in the coil is produced.
Observation from the Faraday’s apparatus
It can be inferred from the experiment that the opening and closing of the switch produces a current in the coil, which is detected in the galvanometer. The current is induced due to a change in a magnetic field, and the EMF is induced due to changing magnetic field. Any change in the current flowing in the coil induces an EMF, and so current is produced in the bottom of the coil. No current is found in the galvanometer either when the switch is open or closed.
How EMF is produced
EMF is produced in the coil when a bar magnet is pushed in and out of it. Opposite signs produce EMF in opposite directions. The outcome will be the same if the coil is then the magnet which indicates that the relative motion is important. The faster the motion the more will be the EMF, and there will be no EMF produced when the magnet is static to the coil.
For example, in generators, a coil is rotated in a magnetic field, which induces an alternating current EMF that depends on the rotation rate,i.e. greater the speed, the greater the magnitude of EMF, which results in a greater current.
Relation between EMF and current
Faraday’s law says that the EMF that is induced in the loop is directly proportional to the rate of change that is caused by the magnetic flux:
EMF=-NdΦ/Δt
EMF is the induced EMF, N is the number of turns, and dΦ is the rate of change of flux in time dt.
Applications
The applications of induced EMF are listed below-
In generators-The EMF is produced by Faraday’s law of induction because of the motion of a circuit and a magnetic field that is employed in generators. When the magnet is moved in relative to the conductor, an electromotive force is induced. If any wire is connected to the electrical load, the current will flow, which generates electrical energy, which helps in converting the mechanical energy of movement of the magnet to electrical energy.
In transforms- When there is a change in the current of the wire, an altering magnetic field is produced. Any conductor in this magnetic field will experience this change as it is linked to the magnetic flux, dΦ/dt. This leads to the creation of an electromotive force which is called the induced EMF of the transformer. If the two ends are connected, then the current will flow.
Induced EMF is used for measuring the flow of electrically conductive liquids and slurries.
It is used is the magnetic stripe on the back of your credit card as used at the grocery store or the ATM.
Conclusion
Faraday verified a fact that an EMF is induced when a conductor is stationary, and the magnetic field is changing by various experiments. Whenever there is motion between the conductor and magnetic field, the flux associated with the coil changes, and this results in a change of voltage developed over the coil, which in turn produces current.
