Applied Electricity Paper 2 , May/June 2012
 Questions: 1 2 3 4 5 6 Main
Weakness/Remedies
Strength

Question 2
1. State Faraday’s law of electromagnetism.
2.  A conductor of active length 0.4 m moving at a velocity of 10 m/s carries a   current of 10 A at right angles to a magnetic field of strength 0.5 T. Calculate the :
3. force exerted;
4. e.m.f. induced in it;
5. power dissipated in watts.
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Observation

1. Faraday’s Law of electromagnetism states that whenever magnetic flux linked with a circuit changes, an emf is always induced in the circuit.

OR If there is a relative motion between a conductor and a magnetic field, an emf is induced in the conductor.

1. (i) l = 0.4 m; v = 10 m/s;  i = 10 A;  B = 0.5 T

F = Bil = 0.5 x 0.4 x 10 = 2 N

(ii) Induced emf, E = Blv
= 0.5 x 0.4 x 10 = 2 V

(iii) Power dissipated, P = Blv x i
= 0.5 x 0.4 x 10 x 10 = 20 W
The question was on Electromagnetic Field. The question was unpopular with the candidates. The candidates were reported to show shallow knowledge of this topic.