Electricity is transmitted from a power station to a distant town using a copper cable of resistance 1.8 Ω1.8\ \Omega1.8 Ω. Power loss occurs because of the resistance of the cable.
The current in the cable is 300 A300\text{ A}300 A.
Calculate the power loss in the cable.
The copper cable is replaced with a new copper cable of the same length. The current remains at 300 A300\text{ A}300 A. The diameter of the new cable is three times the diameter of the original cable.
State and explain how the power loss is affected by this change.
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.