# What is the relation between Work done by electric field, and the work done by an external force?How are these two works related to the change in Kinetic energy?Please explain.

Arun
25750 Points
5 years ago
The work done by the external force is equal to the change in the electrostatic potential energy of the particle in the external field. The change in the potential energy of a charge q when being moved from point A to point B, is the work done by an external force in moving the charge
Khimraj
3007 Points
5 years ago
You can describe the electric force it terms of potential energy, because it is a conservative force. In doing so you actually replace the concept of work done by this force by the concept of potential energy. So you can not longer use both descriptions simultaneously. If you describe the electric force as doing work, then you made positive work and the electric force negative work, so that there is no net gain of kinetic energy in the object. It is a mistake to say that in this description the particle also has potential energy, because in doing so you be considering the work made by the electric field twice (both, as doing work and as gaining potential energy. The descriptions are equivalent, but it is either one or the other. If you chose the potential energy description then you no longer deal with the work of the electric force, as it is implicitly inside the concept of potential energy.