A student is investigating how the resistance of a constantan wire varies with its length.
Describe how an ammeter and a voltmeter should be connected to the constantan wire to measure its resistance.
The student is advised to switch off the circuit between taking readings at different lengths. Explain how this practice improves the accuracy of the investigation.
To make electrical connections along the wire, the student can use either a wide crocodile clip or a sharp-pointed metal jockey. Explain why using a jockey instead of a crocodile clip improves:
39 exam-style questions on AQA GCSE Physics 2.1 Current, potential difference and resistance, covering 2.1.1 Standard circuit diagram symbols, 2.1.2 Electrical charge and current, 2.1.3 Current, resistance and potential difference, and 2.1.4 Resistors. Each one has a worked solution and a mark scheme showing where the marks go.