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

External links

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