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 an equation known as Ohm’s law:
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.
Sign up for articles sent directly to your inbox
Receive news, articles and guides directly from our team of experts.
Written by Leander Oates
Physics19 articlesLeander graduated with First-class honours in Science and Education from Sheffield Hallam University. She won the prestigious Lord Robert Winston Solomon Lipson Prize in recognition of her dedication to science and teaching excellence. After teaching and tutoring both science and maths students, Leander now brings this passion for helping young people reach their potential to her work at SME.
Share this article
written revision resources that improve your