Electricity - AQA GCSE Physics Revision

Topic overview

What you need to know

Electricity is a key part of GCSE Physics. Choose the right model or equation, track units carefully and connect calculations to physical meaning. The rate of flow of electrical charge. I = Q/t (charge ÷ time). Measured in amperes (A). The energy transferred per unit of charge. V = E/Q (energy ÷ charge). Measured in volts (V). A measure of how difficult it is for current to flow. R = V/I. Measured in ohms (Ω).

Exam tip

Write the equation, substitute with units, calculate, then round only at the end.

Revision notes

Core ideas

Secure these ideas first. Say each definition in your own words, then connect it to the topic overview.

Current (I): The rate of flow of electrical charge. I = Q/t (charge ÷ time). Measured in amperes (A).
Potential Difference (V): The energy transferred per unit of charge. V = E/Q (energy ÷ charge). Measured in volts (V).
Resistance (R): A measure of how difficult it is for current to flow. R = V/I. Measured in ohms (Ω).
Ohm's Law: V = IR. The current through a resistor at constant temperature is directly proportional to the potential difference across it.

Revision notes

Apply it in the exam

The exam will rarely ask for an isolated definition. Practise selecting the right idea and using it as part of a complete explanation or method.

Series Circuit: Components connected in a single loop. Current is the same everywhere; voltage is shared between components.
Parallel Circuit: Components connected on separate branches. Voltage is the same across each branch; current splits between branches.
Power (Electrical): P = IV (power = current × voltage). Also P = I²R and P = V²/R. Measured in watts.
Energy Transferred: E = Pt (energy = power × time) or E = QV (charge × voltage). Measured in joules (J).

Core knowledge

Key facts for Electricity

8 essentials

Current (I)

The rate of flow of electrical charge. I = Q/t (charge ÷ time). Measured in amperes (A).

Potential Difference (V)

The energy transferred per unit of charge. V = E/Q (energy ÷ charge). Measured in volts (V).

Resistance (R)

A measure of how difficult it is for current to flow. R = V/I. Measured in ohms (Ω).

Ohm's Law

V = IR. The current through a resistor at constant temperature is directly proportional to the potential difference across it.

Series Circuit

Components connected in a single loop. Current is the same everywhere; voltage is shared between components.

Parallel Circuit

Components connected on separate branches. Voltage is the same across each branch; current splits between branches.

Power (Electrical)

P = IV (power = current × voltage). Also P = I²R and P = V²/R. Measured in watts.

Energy Transferred

E = Pt (energy = power × time) or E = QV (charge × voltage). Measured in joules (J).

Active recall

Close the notes and answer these

1.Without looking, explain current (i) and give one example or consequence.
2.Without looking, explain potential difference (v) and give one example or consequence.
3.Without looking, explain resistance (r) and give one example or consequence.
4.Without looking, explain ohm's law and give one example or consequence.

Content reviewed 23 July 2026 against the current linked specification.

Finished learning?

Mark the notes complete, then test what you can recall.

Previous topicEnergy Stores & Transfers

Official AQA specification