A student investigates how the length of a uniform metal wire affects its electrical resistance. They set up a circuit with a low-voltage cell of 2.5 V2.5\text{ V}2.5 V, an ammeter, a voltmeter, and a length of wire.
Explain why a 2.5 V2.5\text{ V}2.5 V cell does not present an electrical shock hazard to the student.
At a wire length of 0.40 m0.40\text{ m}0.40 m, the current is 0.50 A0.50\text{ A}0.50 A and the potential difference is 2.0 V2.0\text{ V}2.0 V. Calculate the resistance of this length of wire.
Assuming the temperature of the wire remains constant, use the direct proportionality between the wire's length and its resistance to predict the resistance of a 1.20 m1.20\text{ m}1.20 m length of the same wire.
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.