Question

What do you mean by conservation of charge?

Answer 1

Hint: The law of conservation of charge says that electrical charge cannot be created or destroyed. It tells us that the net charge in a system is the same before and after any interaction within the system.

Complete step by step answer:
Conservation of charge is the principle that the total electric charge in an isolated system always remains constant. Mathematically, conservation of charge can be expressed as,
${{\text{Q}}_{\text{initial}}}\text{= }{{\text{Q}}_{\text{final}}}$
Where ${{\text{Q}}_{\text{initial}}}$ is the net charge of the system before the interaction, and ${{\text{Q}}_{\text{final}}}$ is the net charge of the system after the interaction.
So, the conservation of charge implies that the net quantity of electric charge, the amount of positive charge minus the amount of negative charge in the universe, is always conserved. The protons and electrons cannot just appear or disappear out of nowhere, the total charge has to be the same. That is the reason there is always the same number of electrons and protons in a body for that body to be electrically neutral.

Additional information:
An example of the conservation of charge is the process of radioactive decay. In the process, a proton decays into a positron and a neutron, but there is no net charge production. The law of conservation of charge is absolute. It has never been observed to be violated. Therefore, charge is a very special physical quantity and so joins the list of other quantities like energy, momentum and angular momentum which also obeys the conservation laws.

Note:
The law of conservation of charge is very useful since it tells us that the net charge in a system is the same before and after any interaction in the system. But we must ensure that no external charge enters the system during the interaction and that no internal charge leaves the system. The smallest charge that a body can have is the charge of one electron or proton ($1.6\times {{10}^{-19}}\text{C}$).