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





















Question 4
  1. List two types of electrical measuring instrument.
  2. The coil of a moving-coil meter has a resistance of 10 Ω and gives a full-scale deflection when a current of 20 mA passes through it. Calculate the resistance required to enable the instrument to read up to:
    1. 10 A;
    2. 10 V.
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Observation

The expected answers were:

  1. Any two of the instruments stated below
  1. Moving-coil
  2. Moving-iron
  3. Multimeter
  4. Insulation Resistance Meter
  5. Ohmmeter
  6. Wattmeter
  7. Watt-hour meter
  1. (i)  20 x 10-3 x 10 =  9.98 x Rsh                                                        

               Rsh = 0.020 Ω

(ii)
                            
                             20 x 10-3(10 + R) = 10                                 
              R  = 500 – 10 = 490 Ω     

 The question was on Measuring Instruments. It was very popular with the candidates. Many candidates that attempted this question performed well.
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