A213610 Decimal expansion of the characteristic impedance of vacuum in SI units as defined before 20 May 2019.

3, 7, 6, 7, 3, 0, 3, 1, 3, 4, 6, 1, 7, 7, 0, 6, 5, 5, 4, 6, 8, 1, 9, 8, 4, 0, 0, 4, 2, 0, 3, 1, 9, 3, 0, 8, 2, 6, 8, 6, 2, 3, 5, 0, 8, 3, 5, 2, 4, 1, 8, 6, 5, 5, 2, 3, 2, 0, 7, 4, 6, 3, 8, 2, 9, 6, 7, 0, 7, 2, 6, 9, 2, 2, 1, 3, 0, 7, 6, 9, 8, 8, 8, 0, 1, 6, 6, 8, 7, 5, 1, 9, 9, 5, 6, 5, 5, 8, 6, 6, 9, 3, 6, 4, 8

Offset: 3

Author

Stanislav Sykora, Jun 16 2012

Keywords

• nonn
• cons

Comments

Denoted Z_0, this is a function of assigned metrological constants. Regarding these, see A003678 for general context notes, references and links. - Stanislav Sykora, Jun 16 2012

Examples

			376.730313 ... Ohm [also kg * m^2 * s^-3 * A^-2].
		

Links

• Wikipedia, Impedance of free space

Crossrefs

Cf. A003673, A003676, A081823.

Other assigned constants: A003678, A182999, A081799, A019694, A072915, A213611, A213612, A213613, A213614.

Programs

Mathematica

RealDigits[4*Pi*10^-7*299792458, 10, 105] // First (* Jean-François Alcover, Mar 07 2014 *)

Formula

Z_0 = [magnetic_permeability_of_vacuum]*[speed_of_light_in_vacuum] = 10^-6 * A019694 * A003678 = Pi * 119.9169832 Ohms, where 119.9169832 = 4*10^-7 * 299792458 (exact value). [The 2nd equality is valid only for the SI definition that was in effect until 2019.]

Equals 2*alpha*h/e^2, where alpha is the fine-structure constant, h is the Planck constant and e is the elementary charge. The decimal expansion of Z_0 in SI units after the redefinition in 2019 is 2*A003673*A003676/A081823^2. - Jianing Song, Nov 25 2023

Extensions

Edited by Andrey Zabolotskiy, Aug 12 2020