Electric potential Energy of a System of Charge—

The Electric Potential Energy of a system of point charges is defined as the work required to bring the charges constituting the system to their respective position from infinity.

Let we have three point charges q₁, q₂ and q₃ which are initially placed at infinity.

To bring the charge q₁ from infinity to its position, no work is Required.

When q₂ is brought to its position B, q₁ is already present,