The candidates were required to

(a)(i)connect a circuit as shown in the diagram above:
(ii)measure emf of accumulator and record to at least 1 decimal place in volt
(iii)measure value of Vo and record to at least 1 decimal place in volts
(iv)measure value of V1 and record to at least 1 decimal place volts and in trend
Trend: As R increases, V1 decreases.
(v)evaluate five values of V1­¹ correctly and record to at least 3 decimal places

(vi)present data on a composite and complete table showing R, V and V1­¹
(vii)correctly distinguish the graph axes, select reasonable scales, plot the five points correctly and draw a line of best fit into the points;
(viii)draw a large right angled triangle on the graph line, read Δv-1 and ΔR and evaluate slope = Δv-1/ ΔR.
(ix)show, read and record the intercept I on the vertical axis; (x) evaluate y = I/s
(x)evaluate y = I/s

(xi) State any two of the following precautions in acceptable form of speech:
-I removed key when not taking readings;
-I ensured tight connections clean terminals;
-I avoided parallax error in reading voltmeter;
-I corrected for zero error on the voltmeter.

(b)(i)The potential difference (pd) (in volts) between two points in a circuit is the work done (in joules) when one unit of positive charge (coulomb) moves from one point to the other,

               E= IR + Ir

               3 = 0.5x4+0.5r
                r = 3-2. = 2Ώ
                  0.5
This electricity exercise is one requiring candidates to obtain measurements of the
potential dfiference P.d. between two points in an electric circuit.

The knowledge that cell normally has its own internal resistance as well as a possible external load R such that the electromotive force must have to equal the value of the current multiplied by the addition of the resistance R and r was required.

This is exemplified in the graph plotted of the values of V, against the values of R.
When the resistance R reduces to zero, the intercept on the V axis indicates the value of the p.d.

Further the question demanded the precise definition.of the potential difference between two points in a circuit as the P.d. (in volts) being the work done (in Joules) when one unit positive charge moves from one point to another in the electric circuit. Nothing should be lost out of the definition. Most candidates performed poorly in this question.