permeability of vacuum, \(\mu_{0}\)
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https://doi.org/10.1351/goldbook.P04504
Fundamental physical constant by definition equal to 4π x 10E-7 H m-1, exactly.
Source:
Green Book, 2
nd
ed., p. 15 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)