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BS EN ISO 80000-1:2013 pdf free

BS EN ISO 80000-1:2013 pdf free.Quantities and units – General
real scalar quantity, defined and adopted by convention, with which any other quantity of the same kind can be compared to express the ratio of the second quantity to the first one as a number
NOTE 1 Measurement units are designated by conventinally assigned names and symbols.
NOTE 2 Measurement units of quantities of the same quantity dimension may be designated by the same name and symbol even when the quantities are not of the same kind. For example, joule per kelvin and J/K are respectively the name and symbol of both a measurement unit of heat capacity and a measurement unit of entropy, which are generally not considered to be quantities of the same kind. However, in some cases special measurement unit names are restricted to be used with quantities of specific kind only. For example, the measurement unit ‘second to the power minus one’ (1/s) is called hertz (Hz) when used for frequencies and becquerel (Bq) when used for activities of radionuclides. As another example, the joule (J) is used as a unit of energy, but never as a unit of moment of force, i.e. the newton metre (N . m).
NOTE 3 Measurement units of quantities of dimension one are numbers. In some cases, these measurement units are given special names, e.g. radian, steradian, and decibel, or are expressed by quotients such as millimole per mole equal to 10 3 and microgram per kilogram equal to 10-9.
NOTE 4 For a given quantity, the short term “unit” is often combined with the quantity name, such as “mass unit” or “unit of mass”.
NOTE 5 Adapted from ISO/IEC Guide 99:2007, definition 1.9, in which the definition and Note 2 are slightly different and  in which “measurement unit” and“unit” are given as admitted terms.
measurement unit that is adopted by convention for a base quantity
NOTE 1 In each coherent system of units, there is only one base unit for each base quantity.
EXAMPLE In the SI, the metre is the base unit of length. In the CGS systems, the centimetre is the base unit of length.
NOTE 2 A base unit may also serve for a derived quantity of the same quantity dimension.
EXAMPLE The derived quantity rainfall, when defined as areic volume (volume per area), has the metre as a coherent derived unit in the SI.
NOTE 3 For number of entities, the number one, symbol 1, can be regarded as a base unit in any system of units.Compare Note 3 in 3.4.
NOTE 4 Adapted from ISO/IEC Guide 99:2007, definition 1.10, in which the example in Note 2 is slightly different. The last sentence in Note 3 has been added.BS EN ISO 80000-1 pdf download.

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