During building work, a screw pierces a mains cable and creates an unintended connection between the live and neutral wires.
| Quantity | Value |
|---|---|
| Potential difference across the complete fault path | 230 V |
| Total resistance of the complete fault path | 1.15 Ω |
| Resistance of the damaged section next to the screw | 0.15 Ω |
| Fuse rating | 13 A |
Calculate the current in the fault path and the power dissipated in the damaged section next to the screw.
Use your answers to explain why this fault creates a fire risk and how the fuse reduces this risk.
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.