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Physics Paper 1 · P2 · Lesson 2.11

Mains electricity: AC and DC

Recognise the two supplies and remember two UK numbers.

Key ideas1 of 3

Cells supply direct potential difference

With direct current (dc), charge flows in one direction around the circuit. A cell supplies direct potential difference: its terminals keep the same polarity.

Top: charge markers move steadily one way in DC. Bottom: AC markers oscillate back and forth, reversing direction repeatedly.

The markers are a simplified model of charge movement.

Next: Plug wires and electrical safety →
Topic resources and sources

Daily 5 · Exam practice · Extra calculation practice · A4 revision sheet

Start with lessons 2.1–2.6 for the circuit basics. Lesson 2.15 offers extra calculation practice. The P2 specification content is shared by Foundation and Higher Tier; extra practice is not Higher Tier-only.

AQA Combined Science Trilogy specification · 6.2.3.1. Original notes, questions and diagrams. Circuit animations are simplified; motion is deliberately slowed. Measurements and example values are illustrative. All practical circuits use suitable supervised low-voltage apparatus.

Photographs: Photograph of the inside of a UK plug by Alby Reid, Public domain, released by the copyright holder; Electricity pylons near Grafham Water by Mat Fascione, CC BY-SA 2.0; Photoresistor 2 by oomlout, CC BY-SA 2.0. Images displayed without cropping or alteration.