2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/201643We explore consequences of a hypothetical difference between active charges, which generate electric fields, and passive charges, which respond to them. A confrontation to experiments using atoms, molecules, or macroscopic matter yields limits on their fractional difference at levels down to 10^-21, which at the same time corresponds to an experimental confirmation of Newtons third law.6 pages Revtex. To appear in Phys. Rev. AAtomic PhysicsGeneral Relativity and Quantum Cosmologytext