Additivity of Charge

If the sizes of charged bodies are very small as compared to the distances between them, we treat them as point charges. All the charge content of the body is assumed to be concentrated at one point in space. Some other properties of the electric charge are

1. Additive of charges If a system contains n charges q₁, q₂, q₃, …, qn, then the total charge of the system is q₁ + q₂ + q₃ + … + qn .

 Charge has magnitude but no direction. Proper signs have to be used while adding the charges in a system.

In the International System (SI) of Units, a unit of charge is called a coulomb and is denoted by the symbol C.In this system, the value of the basic unit of charge is e = 1.602192 × 10^–19 C. 

______________________________________________________________________________________

Some of these questions which may be asked in your Board Examination 2012-2013

Q1: When a plastic comb is passed through dry hair, what type of charge is acquire by comb?

Q2: Does motion of a body affect its charge?

Q3: What is the origin of frictional forces?

Answer these questions in comment box and help your friends