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

Question 1
1. Explain tolerance with respect to resistors.
2. State the value of the following tolerance found on carbon resistors:
1. silver;
2. Gold.
3. Two resistors R1 = 4 Ω and R2 = 5 Ω are connected in series with a current of 5 A flowing through them. Calculate the:
1. potential difference across each resistor;
2. Total potential difference.

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Observation

1. Tolerance of a resistor defines the upper and lower limits within which the resistance of the resistor must be. This is the 4th colour-band of the colour-code and is expressed in percentage.
1. Colour code                                    Tolerance

Silver                                             10%
Gold                                              5%

1. (i)  Potential difference across the 4 Ω resistor = 4 x 5 = 20 V

Potential difference across the 5 Ω resistor = 5 x 5 = 25 V
(ii) Total potential difference = p.d.4 Ω + p.d.5 Ω
= 20 V + 25 V = 45 V

The question was on Direct Current Circuit Theory. It was well attempted by candidates. The candidates’ performance in parts (a) and (b) of the question was reported to be bad while the part (c) was got by nearly all of them.