A dehumidifier develops a short circuit. A computer model compares a correctly rated fuse with a thick copper link fitted in its place. The model is stopped after 5.0 s if the current has not stopped.
A section of the cable has a resistance of 0.40 Ω.
| Component fitted in the plug | Current in the cable / A | Time the current flows / s |
|---|---|---|
| correctly rated fuse | 30 | 0.80 |
| thick copper link | 30 | 5.0 |
Calculate the energy transferred to this section of cable in each model.
Use your answers to explain why using the fuse reduces the risk of the cable starting a fire.
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.