
Question 2

 Explain briefly how an e.m.f. is induced in a conductor cutting magnetic flux.
 If an e.m.f. of 6 V is induced in a coil when the current in an adjacent coil varies at a rate of 92 A/s, calculate the value of the mutual inductance.


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The expected answers were:
 When a conductor (e.g. a wire) is moved through a magnetic field in such a way that it cuts the magnetic lines of force (i.e. magnetic flux), a voltage is induced in the conductor. An electric current will flow through the conductor if the two ends of the conductor are connected by a wire to form a circuit. Suppose the conductor has a length L metres and moves perpendicularly to the lines of flux in a uniform magnetic field of B tesla at a velocity of V metre per sec., then, in one second, the flux cut,
E = Blv volts
 vL = L
L(mutual inductance) =
= = 65.22 mH
The question was on Electromagnetic Field. The question was unpopular with the candidates. The candidates were reported to show little knowledge of this topic. 


