Dimensional Formula (2 of 2)
- A quantity all of whose dimensional exponents are equal to zero is called a dimensionless quantity and denoted by the symbol 1:
- When a quantity is dimensionless it may be important to know the units that were divided to get the final dimensionless number.
- The notation Q0 shall be used in such cases where Q is the dimensional formula of both the numerator and the denominator.
- Example:
- Radians are defined in terms of length per length or L1L-1
- This reduces to L0, and should not be confused with a mass fraction (M0)
- Dimension formula are important in this International Standard because units with the same dimension formula are directly comparable.
- Attributes allow the use of any unit which satisfies its dimensional formula.
- A unit can be converted into any other comparable unit. Clause 9 defines functions that perform such unit conversion.