Electric Charge 


Electric charge is a characteristic that accompanies fundamental particles, wherever they exist. Benjamin Franklin introduced two types of charges namely positive charge and negative charge based on frictional electricity produced by rubbing two unlike objects like amber and wood. When a glass rod is rubbed with silk, it acquires a force to attract light bodies such as a small piece of paper. The agency which gives the attractive force is said to be electric field or charge. Electric charge is a scalar quantity and its SI unit is coulomb which is denoted by symbol C.

Additivity of Charges

Charges are the scalar quantities and they add up like real numbers. It means that if a system consists of n charges q1,q2,q3........qn  then the total charge of the system will be q1+q2+.....+qn.

Conservation of Charge

The total charge of an isolated system is always conserved ie., initial and final charge of the system will be same.

Quantisation of Charge

 A charge exists discrete amount rather than continuous value and hence quantised in the nature. Mathematically, the charge on an object ie, q=+ - ne 

where, n is integer and e is an electric charge This quantisation of charge is proceed by Millikan's oil-drop experiment.