A metal toaster is connected to the mains by live, neutral and earth wires, with a fuse in the live wire. After a repair, the earth wire is not reconnected to the metal casing. A fault then causes the live wire to touch the casing.
Which statement describes what happens as a result of the fault?
The casing becoming live makes the fuse melt immediately, so the casing is disconnected despite the broken earth path.
The disconnected earth wire opens the normal operating circuit, so no current can reach the metal casing.
The neutral wire carries a large fault current from the casing back to the supply, so the fuse melts.
The casing becomes live, but the broken earth path prevents a large fault current, so the fuse stays intact.
81 exam-style questions on Edexcel GCSE Physics 10.4 Mains electricity, covering 10.4.1 Direct and alternating current, 10.4.2 Live, neutral and earth wires; safety, 10.4.3 Mains wire potential differences and dangers, and 10.4.4 Power ratings and energy use. Each one has a worked solution and a mark scheme showing where the marks go.