Template:Base quantities and count: Difference between revisions

Revision as of 05:23, 17 May 2020

Base quantity	Symbol for quantity	Symbol for dimension	Name of SI unit	Symbol for SI unit
length	l	L	meter	m
mass	m	M	kilogram	kg
time	t	T	second	s
electric current	I	I	ampere	A
thermodynamic temperature	T	Θ	kelvin	K
amount of substance ^*	n	N	mole	mol
count ^*,§	N	C	counting unit	x
luminous intensity	I_v	J	candela	cd

^* For the quantities n and N, the entities X have to be specified in the text or indicated by a subscript or in parentheses: n_X; N_X.

^§ 'Count' is synonymous with 'number of entities'; the name, symbol and unit are not included in the SI as a base quantity or base unit.

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+[[File:SI-units.png|right|200px|link=https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochure-9-EN.pdf]]
 ::::: {| class="wikitable"
 |-
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 | thermodynamic temperature || ''T'' || Θ || kelvin || K
 |-
-| [[amount]] of substance<sup>*</sup> || ''n'' || N || mole || mol
+| [[amount]] of substance <sup>*</sup> || ''n'' || N || mole || mol
 |-
-| [[count]]<sup>*,#</sup> || ''N'' || C || counting unit || x
+| [[count]] <sup>*,§</sup> || ''N'' || C || counting unit || x
 |-
 | luminous intensity || ''I''<sub>v</sub> || J || candela || cd
 |}
-:::: <sup>*</sup> For the quantities ''n'' and ''N'', the entities X have to be specified in the text or indicated by a subscript or in parentheses (IUPAC). [[Concentration]] is expressed as amount of substance concentration, ''c''<sub>X</sub> = ''n''<sub>X</sub>·''V''<sup>-1</sup> [mol·L<sup>-1</sup>], count concentration, ''C''<sub>X</sub> = ''N''<sub>X</sub>·''V''<sup>-1</sup> [x·L<sup>-1</sup>], or other [[format]]s.
+:::: <sup>*</sup> For the quantities ''n'' and ''N'', the entities X have to be specified in the text or indicated by a subscript or in parentheses: ''n''<sub>X</sub>; ''N''<sub>X</sub>.
-:::: <sup>#</sup> 'Count' is synonymous with '[[number of entities]]' and is one of the most fundamental quantities in physics, but the name, symbol and unit are not included in the SI as a base quantity or base unit. Not all sample types contain countable objects. An 'entity', X, is a countable object or event. Countable objects are particles, such as electrons, molecules, packaging units (parcels), cells, organisms, individuals, patients. 'Number of entities' and 'number' are distinguished (in German: Anzahl ''versus'' Zahl). The count is not a pure dimensionless number, but the dimension of the count, C, is the entity. The magnitude of a count, ''N'', is expressed by a pure number times the 'counting unit' [x], indicating how many times different members of the defined entity are ''accounted'' for in a defined system (not how many times the same member of the defined entity is re-counted in the system — consider the political problem of counting votes), or how many times a defined event is counted during a defined period of time. ''N'' is the count [x], and ''N''/''t'' is the frequency (counts per time in units of counting units per second [x·s<sup>-1</sup>]). A prefix can be used with the unit [x], like with any other symbol of SI units: Mx = 10<sup>6</sup> x; µx = 10<sup>-6</sup> x; Gx = 10<sup>9</sup> x; nx = 10<sup>-9</sup> x.
+:::: <sup>§</sup> '[[Count]]' is synonymous with 'number of entities'; the name, symbol and unit are not included in the SI as a base quantity or base unit.