A metal wire of length L L\,L and cross-sectional area A A\,A has a resistance of RRR. A second wire, made of the same metal, has a length of 3L and a cross-sectional area of 2A.
What is the resistance of the second wire?
23R\frac{2}{3}R32R
32R\frac{3}{2}R23R
5R5R5R
6R6R6R
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.