Today we did an experiment with a solenoid through which we varied the current. Around this solenoid, was a different circuit (not coupled to the coil-circuit) where we measured the potential across a resistor. By varying the current my teacher showed how the potential over the resistor would vary. Now faradays law essentially says that a time varying magnetic field induces a rotating electric field. ∇xE = -dB/dt So I thought that the above experiment could be explained by the fact that the changing magnetic field induces an electric field which accounted for the electromotive force induced in the other circuit and thus any drop or increase in potential. BUT! As my friend correctly stated, the only place where the B-field is non zero is inside the solenoid itself. The circuit of the resistor was not a part of the inside of the solenoid. So -dB/dt would have to be zero for all points in space except inside the it. And that means no electric field can possibly have been induced from the varying magnetic field in the solenoid into the circuit of the resistor. So how is the above experiment explained?