Conservation of Charges ( Electrostatics )

Charged is conserved:

When a glass rod is rubbed with silk a positive charge appears on the rod. Measurement shows that a corresponding negative charge appears on the slick. This suggests that rubbing does not create charge but merely transfers it from one object to another, distributing slightly the electrical neutrality of each.
This is hypothesis of conservation charge both for atomic and nuclear level.

1) An interesting example of charge conservation comes about when an electric charge and positron are bought close to each other. The two particles may simply disappear, converting all their rest energy into radiant energy. The radiant energy may appear in the form of two oppositely directed gamma rays of total enegy (2mc^2 ).

The net charge is zero both before and after the event, and the charge is conserved.

2) Certain uncharged particles, such as the neutral meson are permitted to decay electromagnetically into two gamma rays.

This decay conserves charge,the total charge again being 0 before and after the decay.

3) A neutron (q=0) decays into a proton and an electron plus another neutral a neutrino (q=0). The total charge is zero both before and after the decay and charge is conserved.

The decay of an electron (q=-e) into neutral particles, such as gamma rays or neutrino is forbidden e.g.

Because that decay would violate charge conservation. If the decay does occur, the electron must have a life time of the least 10^22 years.

4) Charge conservation is found in the fusion of two deutriun nuclei ( called heavy hydrogen ) to make helium.

The deuterium nucleus contains one proton and one neutron and therefore has a charge of '-e'. The nucleus of the isotope of hydrogen with mass 3, written H^3 and known as tritium contains one proton and two neutron, and thus also has a charge of '+e'. The first reaction therefore has a net charge of +2e on each side and conserves charge. In second reaction, the neutron is unchanged, while the nucleus of the isotope of helium with mass 3 contains two protons and one neutron and therefore has a charge of +2e. The second reaction thus also conserve Charge.