Difference between revisions of "Template:Base quantities and count"
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:::: <sup>*</sup> For the quantities ''n'' and ''N'', the entities X have to be specified and should | :::: <sup>*</sup> For the quantities ''n'' and ''N'', the entities X have to be specified and should be indicated by a subscript or in parentheses (IUPAC). | ||
:::: <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 in counting votes), or how many times a defined event is counted during a defined period of time. ''N'' [x] is the count, and ''N''/''t'' [x·s<sup>-1</sup>] is the frequency (counts per time in units of counting units per second). 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' 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 in counting votes), or how many times a defined event is counted during a defined period of time. ''N'' [x] is the count, and ''N''/''t'' [x·s<sup>-1</sup>] is the frequency (counts per time in units of counting units per second). 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. | ||
Revision as of 08:49, 16 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; number of entities*,# N C counting unit x luminous intensity Iv J candela cd
- * For the quantities n and N, the entities X have to be specified and should be indicated by a subscript or in parentheses (IUPAC).
- # '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 in counting votes), or how many times a defined event is counted during a defined period of time. N [x] is the count, and N/t [x·s-1] is the frequency (counts per time in units of counting units per second). A prefix can be used with the unit [x], like with any other symbol of SI units: Mx = 106 x; µx = 10-6 x; Gx = 109 x; nx = 10-9 x.
