The e.m.f. may be generated by different ways, by heating thermocouples, by chemical action, etc. Whereas the most popular and extensively used method of generating an e.m.f is based on electromagnetism.
After the magnetic effects of an electric current, endeavors were made to produce electric current with the support of magnetism rather than receiving magnetism due to current carrying conductor. This was invented an English Physicist, Michael Faraday in 1831 succeeded in getting e.m.f. from magnetic flux. The occurrence by which e.m.f. is attained from flux is called electromagnetic induction.
Let us study 1st the experiment conducted by Faraday’s to urge understanding of magnetic force induction.
Consider a coil having 'N' tums connected to a meter called galvanometer as shown within the Fig. Meter indicates flow of current within the circuit, if any. A static magnet is affected relative to coil, specified magnetic lines of force related to coil get modified. Whenever, there's motion of static magnet, meter deflects indicating flow of current through the circuit.
The deflection continues as long as motion of magnet exists. More quickly the magnet is affected, the larger is that the deflection. Currently deflection of galvanometer indicates flow of current. However to exist flow of current there should be presence of e.m.f. Hence such movement of flux lines with reference to coil generates e.m.f that drives current through the coil. This can be things wherever coil within which e.m.f is generated is fastened and magnet is affected to form relative motion of flux with reference to coil.
Similar observations will be created by moving a coil within the magnetic field of fastened static magnet, making relative motion between flux and coil. This arrangement is also shown within the Fig. The coil AB is affected by some external suggests that within the magnetic field of fastened permanent magnet. Coil is connected to meter.
Whenever conductor AB is moved within the direction showed in the Fig. the meter deflects indicating flow of current through coil AB. Similarly larger is that the deflection if conductor is hurried in magnetic field.
In each case, primarily there is modification of flux lines with respect to conductor i.e there's cutting of the flux lines by the conductor within which e.m.f. induced.
With this experiment Faraday's expressed Laws referred to as Faraday's Laws of Electromagnetic Induction.
Thus, to possess induced e.m.f. there should exist,
- A coil or conductor.
- A magnetic field (permanent magnet or electromagnet).
- Relative motion between conductor and magnetic flux (achieved by moving conductor with reference to flux or moving with reference to conductor.)