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2. Electricity

Current, potential difference and resistance

6 lessons
2.1 Circuit symbols and diagrams The standard circuit symbols for cells, switches, lamps, resistors, meters and sensors, and how to draw a correct circuit diagram. AQA Edexcel OCR 2.2 Charge and current Electric current as the rate of flow of charge, the equation Q = It, conventional current, and why the current is the same everywhere in a series loop. AQA Edexcel OCR 2.3 Potential difference and resistance Potential difference as energy transferred per unit charge, resistance, the equation V = IR, the energy equation E = QV and how a variable resistor changes the current. AQA Edexcel OCR 2.4 I-V characteristics The current-potential difference graphs of a resistor, a filament lamp and a diode, why their shapes differ, and how to find resistance from a graph. AQA Edexcel OCR 2.5 Required practical: I-V characteristics Required practical: investigate the I-V characteristics of a resistor, a filament lamp and a diode, including the circuit, method, results and precautions. AQA Edexcel OCR 2.6 LDRs and thermistors How the resistance of an LDR changes with light intensity and of an NTC thermistor with temperature, and how they are used in automatic lights, thermostats and alarms. AQA Edexcel OCR

Series and parallel circuits

3 lessons
2.7 Series circuits The rules for current, potential difference and resistance in a series circuit, with worked calculations. AQA Edexcel OCR 2.8 Parallel circuits The rules for current, potential difference and resistance in a parallel circuit, why total resistance falls when a branch is added, and why homes are wired in parallel. AQA Edexcel OCR 2.9 Required practical: resistance of wires and combinations Required practical: investigate how the resistance of a wire depends on its length, and how resistors combine in series and in parallel. AQA Edexcel OCR

Domestic electricity

3 lessons
2.10 Mains electricity and plugs Direct and alternating potential difference, UK mains electricity, the wires in a three-pin plug, and how fuses, earthing and circuit breakers keep users safe. AQA Edexcel OCR 2.11 Electrical power and energy in the home Electrical power and energy: P = IV, P = I^2 R, E = Pt and kilowatt-hours, appliance power ratings and the heating effect of a current. AQA Edexcel OCR 2.12 The National Grid How the National Grid transfers electrical energy from power stations to homes, and why step-up and step-down transformers reduce energy wasted in the cables. AQA Edexcel OCR

Static electricity

2 lessons
2.13 Static charge How insulators become charged by friction through the transfer of electrons, the forces between charges, sparks and earthing, and the uses and dangers of static electricity. AQA Edexcel OCR 2.14 Electric fields Electric fields around charged objects and between plates, how field strength changes with distance, and how a strong field causes a spark. For Separate Science. Separate only AQA Edexcel OCR