9.2.2—V = W / Q
- Syllabus
- 9702–2028–2029
- Objective
- 9.2.2
- Level
- AS
Voltage is V=W/Q, the work or energy transferred per coulomb
The potential difference across a component is V=W/Q, so W=VQ is the energy transferred when charge Q crosses it.
Use joules and coulombs, and identify whether W is supplied or dissipated. The sign depends on the chosen direction.
Moving 5 C through a 12 V motor transfers 60 J to mechanical and thermal stores.
A 12 V label is not 12 J total; it means 12 J per coulomb under the specified operating conditions.
ConceptA-Level CAIE Physics AS