Search results
Results From The WOW.Com Content Network
The International Prototype of the Kilogram (referred to by metrologists as the IPK or Le Grand K; sometimes called the ur-kilogram, [1] [2] or urkilogram, [3] particularly by German-language authors writing in English [3] [4]:30 [5]: 64 ) is an object whose mass was used to define the kilogram from 1889, when it replaced the Kilogramme des ...
As with a definition based upon carbon‑12, the Avogadro constant would also have been fixed. The kilogram would then have been defined as "the mass equal to that of precisely 1000 / 196.966 5687 × 6.022 141 79 × 10 23 atoms of gold" (precisely 3 057 443 620 887 933 963 384 315 atoms of gold or about 5.077 003 71 fixed moles).
It had a mass equal to the mass of 1 dm 3 of water at the temperature of its maximum density, which is approximately 4 °C. [13] 1875–1889: The Metre Convention was signed in 1875, leading to the production of the International Prototype of the Kilogram (IPK) in 1879 and its adoption in 1889. [14]
The international prototype of the kilogram (IPK) is an artefact or prototype that was defined to have a mass of exactly one kilogram.. In metrology (the science of measurement), a standard (or etalon) is an object, system, or experiment that bears a defined relationship to a unit of measurement of a physical quantity. [1]
kg/m 3: density: ρ: kilogram per square metre kg/m 2: surface density: ρ A: cubic metre per kilogram m 3 /kg: specific volume: v: ampere per square metre A/m 2: current density: j: ampere per metre: A/m: magnetic field strength: H: mole per cubic metre mol/m 3: concentration: c: kilogram per cubic metre: kg/m 3: mass concentration: ρ, γ ...
The modern kilogram has its origins in the Age of Enlightenment and the French Revolution.In 1790 an influential proposal by Talleyrand called for a new system of units, including a unit of length derived from an invariable length in nature, and a unit of mass (then called weight) equal to the mass of a unit volume of water. [4]
2019 definition: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10 −34 when expressed in the unit J⋅s, which is equal to kg⋅m 2 ⋅s −1, where the metre and the second are defined in terms of c and Δν Cs.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Donate