A researcher is investigating how the electrical resistance of a conductive elastomer strip (used as a strain sensor in soft robotics) varies as it is stretched to different lengths.
Describe how an ammeter and a voltmeter should be connected to the elastomer strip to measure its electrical resistance.
The researcher is advised to switch off the power supply between taking measurements at different stretched lengths. Explain how this practice improves the accuracy of the investigation.
To make electrical contacts at specific points along the elastomer, the researcher can use either wide, flat metal clamps or sharp, needle-like contact probes. Explain why using needle-like probes instead of wide clamps 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.