Knowra Charge conservation Charge conservation Charge conservation is the principle that an isolated system’s total electric charge remains constant, even as charge moves between its parts or particles are created and destroyed.
Continuity equation : A local balance equation stating that a conserved quantity changes only through flow across a boundary. Its charge form says changing charge density is balanced by electric current flowing in or out.
Electric charge : A property of matter and fields that determines electromagnetic interactions and comes in positive and negative forms. Conservation tracks the net amount of this property across an isolated system.
Electron–positron annihilation : A process in which an electron and positron interact and convert their energy into other particles, often photons. The initial net charge is zero, matching the neutral final photons.
Baryon number : A quantum number equal to the number of baryons minus antibaryons in a system. Unlike electric charge, baryon number is an approximate symmetry that may not hold in all theories.
Electric current : The rate at which electric charge passes through a surface. Current is the flow term that carries charge between regions without changing the total.
Charge density : Electric charge per unit volume, area, or length, depending on the physical description. It describes how conserved charge is distributed locally before accounting for its flow.
Pair production : The creation of a particle and its antiparticle from energy or an interaction with matter. Opposite charges are created together, preserving the initial net charge.
Lepton number : A quantum number assigned to leptons and antileptons, with conventions that distinguish lepton families. It is a separate particle-accounting rule, not a consequence of electric charge conservation.
Gauss's law : A Maxwell equation relating electric flux through a closed surface to the charge enclosed. Together with charge continuity, it links changing electric fields to charge flow.
Isolated system : A system that exchanges neither matter nor energy with its surroundings in an idealized model. Conservation applies to the system’s total charge when no charge crosses its boundary.
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