With electromagnetism the energy fall off depends on the radius and the wavelength. If the wavelength is is greater than a certain amount of the radius (the Fr

With electromagnetism the energy fall off depends on the radius and the wavelength. If the wavelength is is greater than a certain amount of the radius (the Fraunhofer distance) then the energy fall off is a linear 1/r. This is called the near field. http://en.wikipedia.org/wiki/Near_and_far_field http://en.wikipedia.org/wiki/Near_and_far_field