[VIM3] 1.19 quantity value

value of a quantity, value
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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:

112 m−1

EXAMPLE 4 Celsius temperature of a given sample:

−5 °C

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:

43.5 HRC

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:

1.76 µmol/kg

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 product of a number and a measurement unit (see Examples 1, 2, 3, 4, 5, 8 and 9); the measurement unit one is generally not indicated for quantities of dimension one (see Examples 6 and 8), or

- 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").



2 Measurement