Basic Electronics Paper 2, Nov/Dec 2015

Question 4

(a). (i)  Define electromagnetic induction.

(ii) State Faraday’s law of electromagnetic induction.

(b). A straight conductor carrying a current of 50A is located at right-angle to a magnetic field of flux density 2.4T. Calculate the force experienced by the conductor if it is 1.5m long.

 

 

Observation

   The expected answers were;

(a). (i) Electromagnetic induction is defined as the generation of e.m.f when there is                 

     relative motion between a conductor and magnetic flux linking the conductor.

(ii) Faraday’s law of electromagnetic induction states that when there is a relative    
motion between a conductor and a flux linking it, an e.m.f is induced. The      
magnitude of induced e.m.f is directly proportional to the rate of change of flux   
linkages.

 

(b). F = BIL(Sinθ)

F = 2.4 x 50 x 1.5 (Sin 900)
F = 180 x 1
F = 180 N

 

Electromagnetic induction is one topic that has been repeated severally and one would have expected that candidates will come well prepared for the question. It may be defined as the phenomenon in which a potential difference is developed across the terminals of a conductor for which flux linkage varies with time. This definition is the first part of Faraday’s law of electromagnetic induction with the second part as “the magnitude of the induced e.m.f is directly proportional to the rate of change of lux linkage”. Performance was again very poor in this question.