What is the energy of an electric field?

摘要

Today, most people think that an electric field has static energy. Therefore they think that after all energy of some place is changed to kinetic energy, the place cannot give another electric energy. On the contrary, a few people think that electron radiates photons continuously and those photons make electric field. This means the energy of an electric field is not static, it is moving with light speed. A simple experiment was performed to confirm which one is correct. In this experiment, a charged box conductor was moved to right by an electrostatic force in an electric field, then it was returned on the same path by tension of a thread. The measured return point shows the conductor was given the same energy from the electric field on the return path.