Applied Electricity Paper 2 , Nov/Dec. 2014

Questions:		1	2	3	4	5	6		Main

General Comments
Weakness/Remedies
Strength

Question 1
⦁ State Ohm’s law. ⦁ Calculate the resistance of a conductor that has a conductance of 20 µS. (c) An electric heater consumes 2.16 MJ when connected to a 240 V supply for 30 minutes. (i) power rating of the heater; (ii) current taken from the supply.
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Observation
The expected answers were: 1(a) Ohm’s law states that the current I, flowing through a metallic conductor is directly proportional to the potential difference across its ends provided temperature and all other physical factors are kept constant. OR V α I or I α V V = kI where V=voltage, I= current and k is the constant of proportionality (b) Conductance, in Siemens, G = OR R = R = R= 50 kΩ (c)(i) Power rating of heater, P = = = 1200 J/s = 1.2 kW (ii) I = = = 5 A The question was on Direct Current Circuit Theory. The question was popular with the candidates The performance was reported good.