An electrical circuit is used to monitor the temperature inside an automated greenhouse. The circuit consists of a 6.0 V6.0\ \text{V}6.0 V battery, a fixed resistor of resistance 150 Ω150\ \Omega150 Ω, and a thermistor connected in series. A voltmeter is connected in parallel across the thermistor.
At a particular temperature, the potential difference across the thermistor is 2.4 V2.4\ \text{V}2.4 V. Calculate the potential difference across the 150 Ω150\ \Omega150 Ω resistor.
At a different temperature, the resistance of the thermistor decreases until it is equal to 150 Ω150\ \Omega150 Ω. Find the potential difference across the thermistor at this temperature and give a reason for your answer.
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.