----- Original Message ----- From: [email protected] Date: Wednesday, September 30, 2009 6:09 pm Subject: Re: correction /Re: [Vo]:The Electric Field Outside a Stationary Resistive Wire Carrying a Constant Current
> In reply to Harry Veeder's message of Wed, 30 Sep 2009 00:52:54 - > 0400:Hi, > [snip] > >The complete circle/loop/circuit is this: > > > >'negative' to 'negative' (with a 'positive' in between). > > The "'positive' in between" is what makes the equations work out. I > think you > are having a problem because you expect the net EMF to integrate to > zero (begin > point = end point), which it would do if you take the "step" into > account. Note > that the EMF does not change monotonically around the complete > loop. It does > along the wire (assuming a constant resistance/length ratio), > however there is > at least one step when you hit the electrodes. (In the case of a > battery perhaps > more accurately one step at each electrode). > Regards, > > Robin van Spaandonk > > http://rvanspaa.freehostia.com/Project.html > Explaining the steady current in terms of EMFs does not lead to a contradiction so this is not where my problem lies. However, if the steady current is rigorously explained in terms of electric fields a contradiction seems to arise. The steady current requires that the electric field lines around the loop (i.e. from '-' to '-') form a closed path, otherwise the current would be fleeting instead of steady. On the other hand this contradicts the rule that electric fields cannot form a closed loop when the B field is not varying as is the case with a *steady* current. Harry
