Pearson Edexcel International GCSE Physics · specification 4PH1 · Paper 1 | Whole paper: Core content, all eight topics · Free · no account needed
2(c) Energy and voltage in circuits (4PH1 specification)
Series and parallel circuits, resistance, and the graphs that identify a component from its behaviour.
Learn it on Incandio
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.
- Charge and Current — What is actually moving in a wire, how fast it is really going, and why the arrows on every circuit diagram point the wrong way.
- 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.
- Voltage as Energy per Charge — What a volt actually is — and why knowing that turns three separate equations into one idea.
The teaching route this belongs to: Topic 2 · Electricity (Physics) — the lessons in order, with every gate.
Specification coverage
Topic 2 Electricity (c) Energy and voltage in circuits — statements 2.10–2.21
Assessment objectives: AO1, AO2, AO3. Suggested learning time: 70 minutes.
Required knowledge
- Circuit diagrams using standard symbols
- Current as the rate of flow of charge; current in series and parallel circuits
- voltage = current × resistance, V = IR
- Current–voltage graphs for a resistor at constant temperature, a filament lamp and a diode
- How resistance changes in a filament lamp as current increases, and in an LDR and thermistor with light and temperature
- Energy transfer in a circuit and the role of voltage
Required skills
- Calculate total resistance in series
- Interpret an I–V graph to identify a component
- Explain circuit behaviour in terms of current and voltage rather than 'electricity'
- Describe and evaluate the required practical: Investigate the relationship between voltage, current and resistance for a resistor and a filament lamp.
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
- Practical questions on method, variables, results and sources of error
Common mistakes
- Saying current is 'used up' in a circuit. Current is conserved; energy is transferred.
- Describing a filament lamp's I–V graph as a straight line. It curves because resistance rises with temperature.
- Confusing the axes on an I–V graph, which reverses the meaning of the gradient.
This page maps the specification. The pages above teach it, and the Physics lessons hold the whole course — completely free.