No, it's not a mistake. The claim here was that "magnetic force decayed by 1/r³" which is the result of seeing a dipole ("two sources") from far away. Each pol

No, it's not a mistake. The claim here was that "magnetic force decayed by 1/r³" which is the result of seeing a dipole ("two sources") from far away. Each pole decays by 1/r² and the net result (the combined effect of both poles on a test particle) is proportional to 1/r³ I would look at these: https://physics.stackexchange.com/questions/184211/why-does-the-field-of-an-electric-dipole-drop-off-as-1-r3 https://physics.stackexchange.com/questions/184211/why-does-... https://physics.stackexchange.com/questions/293310/why-does-magnetic-force-vary-in-proportion-to-the-cube-of-the-distance-instead-o/ https://physics.stackexchange.com/questions/293310/why-does-... And understand both electrostatic and magnetic dipoles in analogous terms.