Superposition Principle of Electric Force

Superposition principle of electric force

In order to find the resultant force, all charges are considered separately with that particular charge as if all other charges are absent. In this way, for each charge, the force on that particular charge is to be found out. Then the vector sum of all the forces gives the resultant force on that charge. It is called the superposition principle of electric force.

Explanation

Let three positive charges q₁, q₂, and q₃ be located at a close distance [Figure]. Now, the repulsive force on q₃ due to charges q₁ and q₂ is to be found out. First, let us find both the magnitude and direction of the force F₃₁ acting on charge q₃ due to charge q₁₁. Similarly, magnitude and direction of the force F₃₂ acting on q₃ due to q₂ are found out. Now the resultant force F₃ will be the vector sum of F₃₁ and F₃₂, i.e., F₃ = F₃₁ + F₃₂.

It is to be noted that while finding the force on q₃ due to q₁, charge q₂ has been considered to be absent. Similarly, for calculating the force on q₃ due to q₂, q₁ has been considered to be absent. Following this procedure, we can find the net force acting on a charge due to any number of surrounding charges.