OCR Gateway GCSE Physics A topic P3 Electricity overview

Topic P3 Electricity of OCR Gateway GCSE Physics A (specification J249) is about static charge, how circuits behave, and how electrical energy and power are calculated. It is examined on the Paper 1 or Paper 3 side. This page maps the topic and links to a focused answer page for each part.

The P3 Electricity content

Static electricity and charge (P3.1)

Charging insulators by friction, attraction and repulsion, electric fields, and the uses and hazards of static. See Static electricity and charge.

Series and parallel circuits (P3.2)

Circuit symbols, the current and potential difference rules for series and parallel, and how total resistance changes. See Series and parallel circuits.

Current, potential difference and resistance (P3.3)

Current as the flow of charge, the charge equation, potential difference as energy per unit charge, resistance, and $V = IR$. See Current, potential difference and resistance.

I-V characteristics and components (P3.4)

The graphs for a resistor, a filament lamp and a diode, ohmic and non-ohmic behaviour, and thermistors and LDRs. See I-V characteristics and circuit components.

Electrical power and energy (P3.5)

The two power equations, the energy equations, and kilowatt-hour energy and cost calculations. See Electrical power and energy.

How P3 is examined

P3 is assessed on the Paper 1 or Paper 3 side, each paper being 1 hour 45 minutes, worth 90 marks and 50% of the GCSE. Section A is multiple choice; Section B is short answer, structured, maths and practical questions, including a six-mark level of response question. Expect calculations with the charge, resistance, power and energy equations, I-V graph interpretation, circuit reasoning, and kilowatt-hour cost questions. Practical skills from the I-V and circuits activities can be tested.

How to study P3 Electricity

1. Recall every equation. The charge, resistance, two power and two energy equations are all recall for OCR Gateway Physics A.
2. Know the circuit rules. Series shares the voltage with one current; parallel gives each branch the full voltage and splits the current.
3. Read I-V graphs. A straight line is ohmic; a curve (lamp) shows resistance rising with temperature; a diode conducts one way.
4. Learn the sensor components. A thermistor's resistance falls with heat; an LDR's falls with light.
5. Work in kilowatts and hours. For domestic energy and cost, keep power in kilowatts and time in hours.

For the official specification

OCR publishes the full specification, past papers and mark schemes at ocr.org.uk. Always revise from the current specification and OCR's own past papers, because question style and the equation sheet are board-specific.