I Inductor questions (generate a voltage opposing the source voltage?)

[Dale]

Is Faraday's Law, one of the fundamental Maxwell equations, in doubt?

Of course not. The issue is that many posts that were themselves perfectly fine were referring to one of several problematic posts which I deleted. Then the fine posts no longer made sense in context and had to be deleted.

If you did not also receive a warning in conjunction with the deletion, then your post fell into this category

 

[fresh_42]

Lets face it @vanhees71 and @hutchphd , you are not mighty professional scientists, you are puny ungifted amateurs like myself.

This might turn out to be completely wrong!

 

[Delta2]

This might turn out to be completely wrong!

Yes ok it was meant as a joke, we all know vanhees is really excellent and hutchphd is quite good as well.

 

[artis]

Well for what it's worth I don't believe in such "history rewriting" aka cleaning up unless the topic is complete garbage. In this case I think the posts that argued against the viewpoint of @cabraham were I believe informative for anyone else in the future that might stumble upon the same stone.

But as they say, history is written by ment...victors that is!

 

[vanhees71]

I've been only puzzled, why my posting was deleted (I don't even remember which specific one it was), because this is really an issue, where there is nothing to argue about. It's just a direct consequence of Faraday's Law, which (in differential form) is one of the fundamental laws of Nature (i.e., one of the Maxwell equations).

I'd also prefer such threads simply to be closed soon enough with the hint that the question has been clarified by arguments from well-established physics rather than "cleaning them up".

 

[rude man]

What happens there is that the change in the current causes the magnetic field change with time, which induces an EMF (not a voltage, because there's no electric potential...

After the switch is shunted from the battery to a short there is emf developed by L di/dt across the inductor. However, there is also voltage, established as an electrostatic E field equal in magnitude but opposite in polarity to the electromagnetically generated E field, both fields resident within the inductor (zero inductor resistance assumed).
Across the resistor there is no emf but voltage only, equal to that of the inductor (obvious, since they are connected in parallel!).
And of course there is potential also in the electrostatic field.

 

[vanhees71]

You are contradicting yourself since $L \dot{i}$ is nothing else than $\dot{\Phi}$ where $\Phi$ is the flux of the magnetic field and this is equal to the vortex of the electric field, according to Faraday's Law, and this implies that the electric field has no scalar potential.

 

[sophiecentaur]

My former math teacher could solve all of Maxwell's equations and much more but she doesn't know a single thing about how current behaves in actual circuits.

Necessary but not always sufficient.

 

[vanhees71]

There is one and only one E-field. That's what I tried to point out all the time :-(.

 

[berkeman]

This thread needs to be closed; some posts have been deleted as part of the cleanup. Thanks everybody for participating.