# SUPERPOSITION PRINCIPLE OF ELECTROSTATIC FORCE

The topic which we are going to talk about today is one of the important topics of electrostatic. Today we are going to talk about the principle of superposition. This principle is very important and widely used in acoustic, wave optics and current electricity and engineering.

So its becomes very important for us to understand this principle and learn about this.

For understanding the basic concept of superposition principles.

Let’s consider a situation

Think for a charge q1 in the open space, which is surrounded by system of n stationary charges at different distances. The charges which surrounds the charge q1 is q2, q3 ….. and qn

We know that these electrical charges exerts electrostatic force to each other, which can be measured by the coulomb’s Law. But what is the electrostatic force on the charge q1 due to all charges. This is the situation where superposition principle comes into play.

**Superposition principles**–

*According to this principle, force on any charge is the vector sum of all the forces on that charge due to presence other charges at a time. The main feature of this principle is that the individual charge remains unaffected due to presence of other charges.*

The charge which we have thought in the open space i.e the charge q1, will experiences force from the other charges i.e q2, q3 … and qn.

The force experienced by the charge q1 due to other charges q2, q3 ….. and qn is given as –

F12, F13 …. and F1n ……… (1)

According to the superposition principle the total force experienced by the charge q1 is given as –

F = F12 + F13 + …. + F1n

If the distance between the charge q1 and q2 is denoted by r12 and

**r**21 is the unit vector from the charge q2 and q1, thenF12 = [q1q2/(4πε0)r²12]

**r**21Similarly the force on the charge q1 due to other charges is –

F13 = [q1q3/(4πε0)r²13]

**r**31F1n = [q1qn/(4πε0)r²1n]

**r**n1Putting these force in the equation (1) , then we get –

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