Part (a) This was another popular question among the candidates. Many candidates did not record the initial ammeter reading I while few others interchanged the values of I for Io while evaluating
. The determination of Io for which
x -1 = 0 was poor handled. Those candidates that handled it evaluation correctly failed to record the answer to the appropriate number of decimal places. Generally performance was average.
Part (b)
- Was well handled by most responding candidates while most candidates could not do justice to numeral (ii). Most of the candidates could not give the correct formula.
Candidates are expected to:
- Read and record value of ammeter reading I to at least 1 d.p in amperes.
- Correctly record five values of x to at least 1 d.p in cm.
(iii) Read and record five values of Ii to at least 1 d.p in amperes
and in trend
Trend: As 
increases, 
decreases
(iv) Correctly evaluate five values of x –1 to at least 3 d.p.
(v) Show composite table containing 
, x, and
- Plot graph using reasonable scales
- Draw line of best fit
- Determine the slope of the graph
- Evaluate Io for which x -1 = 0 and
- State two of the following precautions.
e.g - Ensured tight connections/clean terminals.
- Key removed when not taking readings
- parallax error avoided in reading ammeter/metre rule
- Avoided sliding the jockey on the potentiometer wire/jockey not allowed
to scratch the wire
- Zero error noted and corrected/avoided on ammeter/ metre rule
- Repeated readings shown on table.
In part (b), the expected answers are:
(b)(i) The emf of a battery is the work done in joules in conveying one coulombs
of charge round a complete circuit
(ii) 
= 
= 
Ey = 1.527V
.