What is resistance?
In GCSE physics, resistance is opposition to the flow of current. Resistance occurs as the electrons flowing in a wire collide with the metal ions that make up the wire. In each collision, energy is transferred from the electron to the metal ion. Because there are so many electrons, the collisions cause the wire to heat up. The hotter the wire, the greater the resistance.
A high resistance means that less current flows in the circuit.
The resistance in a circuit or component can be calculated using the equation below:
V = IR
Where:
V = potential difference (or voltage), measured in volts (V)
I = current, measured in amps (A)
R = resistance, measured in ohms (Ω)
This equation may be presented in its rearranged form in some specifications.
Resistance revision resources to ace your exams
You can strengthen your understanding of resistance by using our revision notes tailored specifically for the AQA, Edexcel, WJEC and OCR exam boards.
You can practice electricity questions and calculations with helpful guidance and examiner tips using our exam board specific GCSE Physics exam questions.
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