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4.2 Electricity

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What are current, potential difference and resistance, and how are they linked?

Current, potential difference and resistance: the meaning of each quantity, the charge equation, Ohm's law and the I-V characteristics of resistors, lamps and diodes.
A focused answer to AQA GCSE Physics 4.2.1, covering current as the rate of flow of charge, potential difference, resistance, Ohm's law and the current-voltage characteristics of ohmic resistors, filament lamps and diodes.
9 min answer →

How is mains electricity supplied to homes, and how is it wired safely?

Domestic electricity and mains: direct and alternating current, the UK mains supply, the three-core cable and the role of the live, neutral and earth wires.
A focused answer to AQA GCSE Physics 4.2.4, covering the difference between direct and alternating current, the UK mains supply values, and the live, neutral and earth wires in a three-core cable and how they keep appliances safe.
8 min answer →

How do we calculate electrical power and energy, and why does the grid use high voltages?

Electrical power and the national grid: the power and energy equations, charge and energy transfer, and why step-up and step-down transformers make transmission efficient.
A focused answer to AQA GCSE Physics 4.2.3 and 4.2.5, covering the electrical power equations, the energy transferred by an appliance, and why the national grid uses step-up and step-down transformers to transmit power efficiently.
9 min answer →

How do current, potential difference and resistance behave in series and parallel circuits?

Series and parallel circuits: the rules for current, potential difference and resistance in each arrangement, and how to combine resistors.
A focused answer to AQA GCSE Physics 4.2.2, covering the rules for current, potential difference and resistance in series and parallel circuits and how total resistance changes when components are combined.
8 min answer →

How does charge build up by friction, and what is an electric field?

Static electricity: charging by friction, the forces between charges, sparking, and the idea of an electric field around a charged object (separate physics only).
A focused answer to AQA GCSE Physics 4.2.6, covering how insulators are charged by friction through electron transfer, attraction and repulsion between charges, how sparks form, and the concept of an electric field around a charged object.
8 min answer →