From: ram@zedat.fu-berlin.de   
      
   Kuan Peng  wrote or quoted:   
   >And there is no law in electromagnetism that defines a “field that   
   >pushes back ” . So, we need to correct Faraday’s law or create a new   
   >law to define the “field that pushes back ”   
      
     The back-reaction of the second coil on the power follows from Ohm's   
     law and Maxwell's equations, but not from Faraday's law alone.   
      
     The second coil has an emf acting on it by Faraday's law.   
     By Ohm's law a current appears in the second coil. According   
     to the Ampere-Maxwell equation (part of Maxwell's equations)   
      
   rot B = μ_0 J + μ_0 e_0 dE/dt,   
      
     a field arises from this current (here you can use the   
     magnetostatic approximation   
      
   rot B = μ_0 J   
      
     ). J here is the current in the second coil.   
      
     A portion of this field creates a magnetic flux through   
     the first coil, which leads to an EMF in the first coil   
     by Faraday's law, increasing the load on the power supply.   
      
     Unicode:   
      
   𝛁 × 𝐁 = μ₀ 𝐉 + μ₀ ϵ₀ ∂𝐄/∂t   
      
   𝛁 × 𝐁 = μ₀ 𝐉  (approximation)   
      
     Summary of some laws:   
      
     Faraday's law states that a time-varying magnetic field induces   
     a circling electric field.   
      
     The Ampère-Maxwell law states that currents and time-varying   
     electric fields produce circling magnetic fields.   
      
     Ohm's law states that the current density through a conductor   
     is proportional to the electric field.   
      
     Lenz's law states that an induced current flows in a direction   
     such that the magnetic field it produces opposes the change   
     in magnetic flux that induced it. It can be derived from   
     Faraday's law, the Ampère–Maxwell law, Ohm's law, and the   
     conservation of energy (or the Lorentz force law).   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)