A student builds the circuit illustrated in Fig. 5.1 in order to determine the resistance of a length of wire. The circuit has four identical cells.
When the switch is closed, the student notices that both meters give zero. This is because the arrangement shown in Fig. 5.1 is unsuitable for carrying out the measurement.
(a)[2]
Describe the modifications to the circuit in Fig. 5.1 that are required so the meters give readings that can be used to calculate the resistance of the length of wire.
(b(i))[2]
Calculate the resistance of the 9.0 cm length of wire.
(b(ii))[1]
Explain whether line Q is produced by a wire length that is longer or shorter than 9.0 cm.
(b(iii))[1]
Calculate the length of wire used to produce line Q.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Substitute an ammeter for the voltmeter” …