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WalesCombined Science

Unit 3 Physics 1: Electricity and the grid

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 related?

Electric current, potential difference and resistance, the equation V = IR, and the current-voltage graphs for a resistor, a filament lamp and a diode.
A focused answer to the WJEC GCSE Science Double Award Unit 3 topic on electricity, covering current, potential difference and resistance, the equation V = IR, and the current-voltage characteristics of a resistor, filament lamp and diode.
9 min answer →

How does mains electricity work in the home, and how do fuses and earthing keep us safe?

Mains alternating current, the live, neutral and earth wires in a plug, the dangers of electricity, and how fuses, circuit breakers and earthing provide safety, with the power equation.
A focused answer to the WJEC GCSE Science Double Award Unit 3 topic on domestic electricity, covering mains alternating current, the three wires in a plug, electrical dangers, fuses, circuit breakers and earthing, and the power equation P = IV.
9 min answer →

How is electricity generated, and how do transformers change the voltage?

Electromagnetic induction in a generator, how a transformer changes voltage, and the difference between step-up and step-down transformers.
A focused answer to the WJEC GCSE Science Double Award Unit 3 topic on generators and transformers, covering electromagnetic induction in a generator, how a transformer changes voltage, and step-up and step-down transformers.
9 min answer →

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

The rules for current and potential difference in series and parallel circuits, and how resistance combines in each.
A focused answer to the WJEC GCSE Science Double Award Unit 3 topic on circuits, covering the rules for current and potential difference in series and parallel circuits, and how the total resistance changes in each.
9 min answer →

How does the National Grid carry electricity efficiently across the country?

The structure of the National Grid and why electricity is transmitted at high voltage to reduce energy loss.
A focused answer to the WJEC GCSE Science Double Award Unit 3 topic on the National Grid, covering its structure and why electricity is transmitted at high voltage and low current to reduce energy loss in the cables.
8 min answer →