1.2.3—SI base units to check the homogeneity of physical equations
- Syllabus
- 9702–2028–2029
- Objective
- 1.2.3
- Level
- AS
Dimensional homogeneity is a necessary check on a physical equation
Every additive term in a valid equation must have the same dimensions, and both sides must match. Dimensions use base quantities such as [L], [T] and [M].
Do not use dimensional analysis to determine dimensionless numerical constants or prove an equation completely; it is a consistency test.
In s=ut+½at², both ut and at² have dimensions L, matching displacement s.
An equation can be dimensionally correct but physically wrong because of a missing factor or incorrect model.
ConceptA-Level CAIE Physics AS