Electron specific charge

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The electron specific charge is a physical constant equal to the electric charge of an electron (the elementary charge) divided by its mass: e/me. It was first measured by J. J. Thomson in 1897,[1] in what was arguably the first application of mass spectrometry. The electron specific charge was historically important as a means to determine the electron mass, and a similar method is now used to measure the electron relative atomic mass. Its current value, based on the 2006 CODATA recommended values,[Note 1] is 1.758 820 149(44) × 1011 C kg−1.

Notes and references

Notes

  1. Jump up The electron specific charge was included in the 1973 set of recommended values, but has not been included since. It may be calculated as (e/me)2 = α5c0/2hR2μ0, with ur = 2.5 × 10−8 (as for h−½).

References

  1. Jump up Thomson, J. J. Cathode rays. Phil. Mag., Ser. 5 1897, 44, 293–316. DOI: 10.1080/14786449708621070.

External links

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