Basic Electronics Paper 2, WASSCE (PC 2ND), 2020

Question 2

       

Figure 1 is a d.c. circuit.

 

Calculate the:

(i) total resistance of the circuit;

(ii) current (I) in the circuit;

(iii) power dissipated in the circuit.

  

 

The expected responses were:

  1. First, each of the two resistors connected in series are reduced to one according to   

R ser-eq= R1 + R2 = 1 + 1(= 2Ω);  2 + 2 (= 4Ω);   2 + 2 (= 4Ω).                 
The resulting equivalent parallel combination will give a total resistance of 
                                                                                                                        

(ii) Current (I) in the circuit is given by:

              

(iii)Power dissipated in the circuit is evaluated as


The Chief Examiner reported that majority of the candidates that attempted this question responded very well. The report indicated that, a very large percentage of them were able to correctly determine the total resistance and apply the appropriate formulas for the calculation of current and power dissipated respectively..