Pearson Edexcel International GCSE Physics · specification 4PH1 · Paper 1 | Whole paper: Core content, all eight topics · Free · no account needed
2(b) Mains electricity (4PH1 specification)
Household electricity: how it is made safe, how much energy it uses, and why the fuse is in the live wire.
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The 5 Incandio pages that teach this — each explained in full, then proved in marked questions, taught back to an AI pupil and defended in a debate. Completely free.
- Resistance and Ohm's Law — What slows the electrons down, the one equation that ties the whole topic together, and when it stops being true.
- Series and Parallel Circuits — Two ways of joining components, and why every building in the world is wired one of them.
- Current–Voltage Graphs, LDRs and Thermistors — The shapes four components make on a graph, and two resistors that deliberately refuse to stay the same.
- Electrical Power and Energy — Why a wire carrying a current gets hot, how fast a device uses energy, and how to pick a fuse.
- Mains Electricity and Safety — What is different about the electricity in a wall socket, and the four things that stand between it and you.
The teaching route this belongs to: Topic 2 · Electricity (Physics) — the lessons in order, with every gate.
Specification coverage
Topic 2 Electricity (b) Mains electricity — statements 2.2–2.9
Assessment objectives: AO1, AO2. Suggested learning time: 70 minutes.
Required knowledge
- The hazards of damaged insulation, overheating cables, damp conditions and excess current
- The use and operation of fuses, circuit breakers and earthing
- Why the fuse and switch must be in the live wire
- The difference between direct current and alternating current
- power = current × voltage, P = IV
- energy transferred = current × voltage × time, E = IVt
Required skills
- Select an appropriate fuse rating from a power and voltage
- Explain a safety feature in terms of what happens to the current
- Calculate energy transferred over a stated time
How it is examined
- Multiple-choice and short-answer recall
- Calculations using the specification's relationships
- Extended open-response applying the physics to an unfamiliar situation
Common mistakes
- Choosing the fuse closest to the current from below. A fuse must be rated ABOVE the normal working current or it blows in normal use.
- Saying the earth wire 'takes the electricity away'. It provides a low-resistance path so a large current flows and the fuse breaks the circuit.
- Putting the fuse in the neutral wire — the appliance would stay live after the fuse blew.
This page maps the specification. The pages above teach it, and the Physics lessons hold the whole course — completely free.