Electrons
The behaviour of electric circuit is to a very large extent dependent on the behaviour of electrons which are the subatomic particles which travel in planetary orbits around the nucleus of an atom. From the nature of the orbital motion of electrons, some characteristics of the electrons can be deduced easily.
Characteristics of an electron
- An electron possesses energy.
- It appears to possess a mass which is a very small fraction of the mass of nucleus around which it travels.
- There must be a force of attraction between the electron and the nucleus to keep it in the curved orbit with which it travels.
Protons
For an electric force of attraction to exist between the electrons and nucleus, the nucleus must contain particles which possess opposite or unlike charge.
These particles are called protons. The electrons posses a negative electric charge and protons possess an opposite (positive) electric charge. The charge on a proton is equal in magnitude to that of an electron. The nucleus of an atom in its normal state contains equal number of protons as electrons. Consequently, the net charge of the atom at its normal state is zero and the atom is electrically neutral. However, protons have a mass of 1837 times of the apparent mass of an electron. The mass of electron is 9.10×10ˉkg.
