|
|
| Line 1: |
Line 1: |
| {{TOCright}}
| | Friends call extended [http://www.team-qnak.com/qnak/index.php?mod=users&action=view&id=8348 car warranty] [http://Extended-car-warranty-services-review.toptenreviews.com/ warranty] her Felicidad and her husband doesn't extended [http://xn--h1aecfj6f.xn--p1ai/content/auto-repair-tips-youll-wish-youd-read-sooner car warranty] [http://Www.ncdoj.gov/Consumer/Automobiles/Extended-Car-Warranties.aspx warranty] like it at all. Alabama has usually been his home and his family members enjoys it. What she loves performing is taking part in croquet and she auto warranty is attempting to make it a occupation. Meter reading is exactly where my [http://www.mass.gov/ocabr/consumer-rights-and-resources/autos/lemon-laws/used-vehicle-warranty-law.html primary] income comes from but soon I'll be on my personal.<br><br>My weblog :: [http://tobynabors.com/ActivityFeed/MyProfile/tabid/61/userId/46195/Default.aspx extended auto warranty] |
| In [[physics]] and [[chemistry]], the '''atomic mass constant''', ''m''<sub>u</sub>, is one twelfth of the mass of an unbound atom of carbon-12 at rest and in its ground state.<ref>{{GoldBookRef |title=atomic mass constant |file=A00497}}</ref> It serves to define the [[atomic mass unit]] and is, by definition, equal to 1 u. The 2010 [[CODATA]] recommended value is {{CODATA2010|constant=u}}.
| |
| | |
| In practice, the atomic mass constant is determined as the ratio of the [[electron rest mass]] ''m''<sub>e</sub> to the [[electron relative atomic mass]] ''A''<sub>r</sub>(e) (that is, the mass of the electron on a scale where {{sup|12}}C = 12).<ref>{{CODATA1998}}</ref> The relative atomic mass of the electron can be measured in [[cyclotron]] experiments, while the rest mass of the electron can be derived from other physical constants.
| |
| :<math>m_{\rm u} = \frac{m_{\rm e}}{A_{\rm r}({\rm e})} = \frac{2R_\infty h}{A_{\rm r}({\rm e})c\alpha^2}</math> | |
| The current uncertainty in the value of the atomic mass constant – one part in 20 million – is almost entirely due to the uncertainty in the value of the [[Planck constant]].
| |
| | |
| ==Energy equivalents==
| |
| The atomic mass constant can also be expressed as its [[mass–energy equivalence|energy equivalent]], that is ''m''<sub>u</sub>''c''<sup>2</sup>. The 2010 CODATA recommended values are:
| |
| :{{CODATA2010|constant=tuj}}
| |
| :{{CODATA2010|constant=muc2mev}}
| |
| The [[Electronvolt|megaelectronvolt]] (MeV) is commonly used as a unit of mass in [[particle physics]], and these values are also important for the practical determination of relative atomic masses. Although relative atomic masses are defined for neutral atoms, they are measured (by [[mass spectrometry]]) for ions: hence, the measured values must be correct for the mass of the electrons that were removed to form the ions, and also for the mass equivalent of the [[electron binding energy]], ''E''<sub>b</sub>/''m''<sub>u</sub>''c''<sup>2</sup>. The total binding energy of the six electrons in a carbon-12 atom is 1030.1089 eV = {{nowrap|1.650 4163{{e|−16}} J}}: ''E''<sub>b</sub>/''m''<sub>u</sub>''c''<sup>2</sup> = {{nowrap|1.105 8674{{e|−6}}}}, or about one part in 10 million of the mass of the atom.<ref>{{CODATA2002}}</ref>
| |
| | |
| == See also ==
| |
| *[[Atomic mass]]
| |
| | |
| ==References==
| |
| {{reflist}}
| |
| | |
| ==External links==
| |
| *[http://physics.nist.gov/PhysRefData/Compositions/ Atomic weights and isotopic compositions]
| |
| | |
| [[Category:Amount of substance]]
| |
| [[Category:Physical constants]]
| |
Friends call extended car warranty warranty her Felicidad and her husband doesn't extended car warranty warranty like it at all. Alabama has usually been his home and his family members enjoys it. What she loves performing is taking part in croquet and she auto warranty is attempting to make it a occupation. Meter reading is exactly where my primary income comes from but soon I'll be on my personal.
My weblog :: extended auto warranty