number and reference together expressing magnitude of a quantity
EXAMPLE 1 Length of a given rod:
5.34 m or 534 cm
EXAMPLE 2 Mass of a given body:
0.152 kg or 152 g
EXAMPLE 3 Curvature of a given arc:
EXAMPLE 4 Celsius temperature of a given sample:
EXAMPLE 5 Electric impedance of a given circuit element at a given frequency, where j is the imaginary unit:
(7 + 3j) Ω
EXAMPLE 6 Refractive index of a given sample of glass:
EXAMPLE 7 Rockwell C hardness of a given sample:
EXAMPLE 8 Mass fraction of cadmium in a given sample of copper:
3 µg/kg or 3 ·10−9
EXAMPLE 9 Molality of Pb2+ in a given sample of water:
EXAMPLE 10 Arbitrary amount-of-substance concentration of lutropin in a given sample of human blood plasma (WHO International Standard 80/552 used as a calibrator):
5.0 IU/l, where “IU” stands for “WHO International Unit"
NOTE 1 According to the type of reference, a quantity value is either
- a number and a reference to a measurement procedure (see Example 7), or
- a number and a reference material (see Example 10).
NOTE 2 The number can be complex (see Example 5).
NOTE 3 A quantity value can be presented in more than one way (see Examples 1, 2 and 8).
NOTE 4 In the case of vector or tensor quantities, each component has a quantity value.
EXAMPLE Force acting on a given particle, e.g. in Cartesian components (Fx; Fy; Fz) = (−31.5; 43.2; 17.0) N.
ANNOTATION (informative) [3 December 2013] The term "quantity value" was chosen as the first (preferred) term in order to take advantage of the adjectival use of a noun in the English language. However, it is recognized that the more commonly used expression is the second term, "value of a quantity", or even the third term, "value" (when there is no possible ambiguity or confusion; for example, it is not necessary to write "quantity value of a measurand").