(a)[1]
State the name of an apparatus that the student can use to measure the diameter of a wire accurately.
(b(i))[1]
The student records the voltage and current immediately after switching on the circuit. Suggest a reason for taking the readings immediately.
(b(ii))[2]
Fig. 4.2 shows the ammeter and voltmeter when a wire of diameter $0.15\,\text{mm}$ is used. State the current and voltage readings for this wire.
(c)[4]
The student repeats the experiment with a wire of diameter $0.24\,\text{mm}$. The voltmeter reading stays the same. Fig. 4.3 shows the updated ammeter reading.
(d(i))[3]
Complete the results table in Fig. 4.4 for the experiment involving the two wires.
(d(ii))[1]
Use your results to suggest how the diameter of a wire is related to its resistance.