Faraday’s First Law of electromagnetic induction :- states that, “whenever the magnetic flux linking a
conductor or a coil changes, an emf is induced in it”.
It does not matter how the change is brought about and what matters is the change of flux linking.
Faraday’s Second law of electromagnetic induction :- gives the magnitude of the induced emf. It states that ,the magnitude of the emf induced is directly proportional to the rate of
change of flux linkages.
Explanation :- Suppose a coil has N turns. Let the flux through it changes from Φ1 to Φ2 in t seconds. Then by definition of flux linkages
Initial
flux linkage = N × Φ1
and
Final flux linkage = N × Φ2
Final flux linkage = N × Φ2
Therefore, e= ((N × Φ1)-(N × Φ2))
/ t
= N × ( (Φ1-Φ2) / t ) volt
It must have been clear by now
that the induced
emf
magnitude depends on how rapidly the
change takes place i.e rate of change of flux. So, an emf will induce if and only if the flux change.No flux change, no emf.
