The candidates were expected to:

(i) set up a circuit diagram as shown in the diagram above;

(ii) read and record the value of Io in ampere to at least 1 decimal place;

(iii) evaluate and record the value of I¹ to 1 decimal place;

(iv) read and record five values of I in ampere to at least 1 decimal place in trend.

Trend: As R increases, I decreases;

(v) evaluate five values of I¹ to at least 3 significant figures.

(vi) present data in a composite and complete table and

showing at least I, I¹ and R;

(vii) correctly distinguish the graph axes , select reasonable scales, plot the five points and draw a line that best fits the points;

(viii) draw a large right angled triangle on the graph line, read Δ I¹

and ΔR and evaluate slope =__ Δ I¹__

ΔR

(ix) show and read the intercept on the vertical axis;

(x) evaluate k = c/s;

(xi) state any two of the following precautions in the correct form of speech:

- I ensured firm support of pendulum;

- Ensured tight connections/clean terminals

- Zero error of ammeter noted and corrected for;

- Parallax error in ammeter avoided.

b (i) The electromotive force of a cell is the work done in driving a unit of electric charge round a complete circuit OR

The electromotive force is the total work done in driving one coulomb of electricity round the circuit OR

The total energy per coulomb obtained from a cell or battery.

(ii) A galvanometer adapted to read as an ammeter.

This experiment was very popular among the candidates. However, some candidates failed to record their initial ammeter reading; record the reciprocal of I to the required decimal places; evaluate k = c/s.

In part b, many candidates failed to explain electromotive force of a cell correctly. Some candidates could not explain with the aid of a labeled diagram how a galvanometer may be adapted to read as an ammeter.