| Original 1793 : The grave was defined as being the weight [mass] of one cubic decimetre of pure water at its freezing point | At the close of the 19th century three different systems of units of measure existed for electrical measurements: a also known as the Gaussian or ESU system , a SI base units :23 Unit name Unit symbol Definition Incomplete m• It was renamed the " kelvin" symbol "K"; "kelvin" spelt with a lower case "k" in 1967 |
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| March 1976 [First published October 1963] | 012 kilogram of carbon 12 |
| 73 in a of the corresponding to the transition between the 2p 10 and 5d 5 quantum levels of the -86 | Milton, Martin 14 November 2016 |
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| Unit names as adjectives In English, a space is recommended between the number and the unit symbol when used as an adjective, e | Interim 1954 : The 0 |
The definitions of the other base units are more complicated.
5| Current 1889 : The mass of the International prototype kilogram | Clockwise from top: , , , , , and |
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| Since there is no prototype marked 8, this prototype is referred to as 8 41 | Online Categorised Metric Conversion Calculator• Being one thousandth of a cubic metre, the litre is not a coherent unit of measure with respect to SI |
United Kingdom and the former Empire Logo of the American National Metrication Council, an organization set up by to coordinate the country's transition to the metric system.
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