An electrical power station transmits a constant electrical power P P\,P over transmission lines of total resistance RRR. If the transmission voltage is increased from V V\,V to 4V, what is the effect on the power lost as heat in the lines?
The power loss decreases to 116\frac{1}{16}161 of its original value.
The power loss decreases to 14\frac{1}{4}41 of its original value.
The power loss increases by a factor of 444.
The power loss increases by a factor of 161616.
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.