The inverse square law in electrostatics arises from the masslessness of the photon, the force carrier of electromagnetism, as explained in quantum field theory. If photons had mass, the electrostatic potential would follow a different form known as the Yukawa potential, which is influenced by the mass of the photon. Current experiments suggest that the photon mass is extremely small, reinforcing the validity of the inverse square law. Classically, this law is derived from the way electric fields are modeled, where the density of field lines decreases with the square of the distance from the charge. Thus, the inverse square law is a fundamental aspect of electrostatics, closely tied to the nature of electric fields and the properties of photons.
