Discuss the basic properties of electric charges.

Explanation

(i) Electric charge: Most objects in the universe are made up of atoms, which in turn are made up of protons, neutrons and electrons. These particles have mass, and electric charge which are intrinsic and fundamental property of particles. The SI unit of charge is Coulomb.
(ii) Conservation of charge: Benjamin Franklin found that when one object, charges get transferred from one to the other. Before rubbing, both objects are electrically neutral. Rubbing simply transfers the charges from one object to the other. For example, when a glass rod is rubbed against a silk cloth, the negative charge is transferred from glass to silk. Due to this cause, the glass rod is positively charged and the silk cloth becomes negatively charged. From these observations, be concluded that charges are neither created or nor destroyed but can only be transferred from one object to the other. This is called conservation of total charges and forms one of the fundamental conservation laws in physics. It can be stated more generally in the following way. ‘The total electric charge in the universe is constant and charge can be neither created nor destroyed. In any physical process, the net change in charge will always be zero.’
(iii) Quantisation of charge: The charge q on any object is equal to the integral multiple of the fundamental unit of charge e.
q = ne
Here n is an integer `(0, +-1, +-2, +-3, +-4 .........)`. This is called Quantisation of charge.
Robert Milikan in his famous experiment found that the value of `e = 1.6 xx 10^(-19)`C. The charge of an electron is `-1.6 xx 10^(-19)`C and the charge of the proton is `+1.6 xx 10^(-19)`C.