Say we have one spin-less electron in a box in the ground state. Say we have dials on the outside of the box that can vary mass and charge of the spin-less electron. Suppose we start with one spin-less electron in a box with m and e set to as near zero as we please, but not zero. As m and e go to zero should the energy in the box go to zero? Now slowly raise the dial for mass of the spin-less electron in the box to m while keeping the charge near zero. What is the energy in the box, is it mc^2? Assume moving the dial requires a torque, now torque times the angular rotation of the dial gives an energy. Pretend that we transfer energy to the field of the spin-less electron in the box by moving the mass dial from near zero to m. Now slowly raise the dial for the charge of the spin-less electron while holding the mass dial. Assume again that any change in the field energy in the box comes from the energy to change the dials position. Does the energy in the box get bigger by making the charge larger? Is the extra energy stored in the electromagnetic field? As the charge dial is raised is there a torque on the mass dial? Now reverse the order, slowly raise the charge first and then the mass. Is the energy in the box the same for different paths? Thanks for any help!