出典:Wikipedia
出典:『Wikipedia』 (2011/03/17 09:44 UTC 版)
The retarded potential formulae describe the scalar or vector potential for electromagnetic fields of a time-varying current or charge distribution. The retard between cause and effect is thereby essential; e.g. the signal takes a finite time, corresponding to the velocity of light, to propagate from the source point
of the field to the point
where an effect is produced or measured. Otherwise, the formulas below correspond to the same superposition principle acting, e.g., in electrostatics for Coulomb's law.