An experimenter is studying the electrical resistance of various metal wires. All the wires are made of the same alloy but have different lengths and diameters.
After measuring the resistance of a reference wire, which of the following wires is guaranteed to have a smaller resistance than the reference wire?
a longer wire with a smaller diameter
a longer wire with the same diameter
a wire of the same length with a smaller diameter
a shorter wire with a larger diameter
452 exam-style questions on CIE IGCSE Physics 4.2 Electrical quantities, covering 4.2.1a Positive and negative charge, 4.2.1b Charging by friction and detecting charge, 4.2.1c Electrical conductors and insulators, 4.2.1d Electric fields and electric field patterns, 4.2.2a Electric current, charge and measuring current, 4.2.2b Conduction in metals and the direction of current, 4.2.2c Direct current and alternating current, 4.2.3a Electromotive force, 4.2.3b Potential difference and voltmeters, 4.2.4a Resistance, 4.2.4b Resistance of a metallic wire, 4.2.4c Current–voltage graphs, and 4.2.5 Electrical energy and electrical power. Each one has a worked solution and a mark scheme showing where the marks go.