A constant {fine-structure constant} {coupling constant} measures electromagnetism force strength (Sommerfield) [1916]. It has no dimensions. It equals 7.297 * 10^-3 ~ 1/137. The fine-structure constant depends on electron charge, Planck constant, light speed, and permittivity or permeability or Coulomb constant. The coupling constant measures photon-electron force.
Physical Sciences>Physics>Electromagnetism>Force
5-Physics-Electromagnetism-Force
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Date Modified: 2022.0224