Electrical Charge and it's properties.

Charge is the fundamental property of a material body due to which electrical forces arises.

When a piece of amber is rubbed with fur, it acquires the property of attracting light objects like bits of paper.

In the 17th  century, William Gilbert discovered that, glass, ebonite etc, also exhibit this property, when rubbed with suitable materials. The substances which acquire charges on rubbing are said to be ‘electrified’ or charged.

These terms are derived from the Greek word elektron, meaning amber. The electricity produced by friction is called frictional electricity. If the charges in a body do not move, then, the frictional electricity is also known as Static Electricity.

Charge is of two types:
Positive charge
Negative charge

Basic properties of electric charge

(i) Quantisation of electric charge

The fundamental unit of electric charge (e) is the charge carried by the electron and its unit is coulomb.  e  has the magnitude 1.6 × 10^−19  C. In nature, the electric charge of any system is always an integral multiple of the least amount of charge. It means that the quantity can take only one of the discrete set of values. The charge,  q = ne  where n  is an integer.

(ii) Conservation of electric charge

Electric charges can neither be created nor destroyed. According to the law of conservation of electric charge, the total charge in an isolated system always remains constant. But the charges can be transferred from one part of the system to another, such that the total charge always remains conserved.

(iii) Additive nature of charge

The total electric charge of a system is equal to the algebraic sum of electric charges located in the system. For example, if two charged bodies of charges +2q,  −5q are brought in contact, the total charge of the system is –3q.