9.3.2—V = IR
- Syllabus
- 9702–2028–2029
- Objective
- 9.3.2
- Level
- AS
Ohm’s law is V=IR when resistance remains constant
Ohm’s law states that current is directly proportional to potential difference for a conductor at constant physical conditions: V=IR.
Check temperature and other conditions before applying it. Rearrange only after identifying which quantity is unknown.
A 10 Ω resistor at 5.0 V carries 0.50 A, provided its temperature remains effectively constant.
V=IR defines resistance at a point, but Ohm’s law requires a straight-line proportional relationship over the tested range.
ConceptA-Level CAIE Physics AS