Potential Difference Equation
V = E / Q
Voltage (V) = Energy transferred (J) ÷ Charge (C)
Potential difference (p.d.) is the energy transferred per unit charge as charges pass through a component.
- 1 Volt = 1 Joule per Coulomb (1 V = 1 J/C)
- A 6 V battery gives 6 J to every coulomb
- A lamp with 6 V across it takes 6 J from every coulomb
Two contexts for voltage:
- EMF (electromotive force) — voltage across a power supply (energy given to charges)
- p.d. (potential difference) — voltage across a component (energy taken from charges)
This deep dive covers Understanding Potential Difference within Potential Difference for GCSE Physics. Revise Potential Difference in Electricity for GCSE Physics with 14 exam-style questions and 30 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 14 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Potential Difference
Which of the following is the correct definition of potential difference?
Explain what is meant by a potential difference of 6 V across a component.
Quick recall flashcards
What is 1 Volt?
1 Joule per Coulomb (1 V = 1 J/C)
P.d. equation?
V = E/Q where V = voltage (V), E = energy (J), Q = charge (C). Also V = IR.