Recent content by EMGuy101

Some things to point out: E=-grad(V) - dA/dt curl(E)= curl(-grad(V) - dA/dt), curl of grad(V)=0 curl(E)=-curl(dA/dt) curl(E)=-d(curl(A)/dt curl(E)=-dB/dt but E=-dA/dt in this case not grad(V) since it is being generated by faradays law. THUS, by saying curl(E)=0 does not mean...

Maybe you should take the time to write out EXACTLY what it is you do not understand. I am not sure what it is that is confusing you. I believe that quote is essentially saying that the E field outside the solenoid is not a conservative field (as one might assume if you say that the curl(E)=0).

Something that might help you understand why this is true is magnetic field lines have to close on themselves (i.e. no such thing as a magnetic monopole). The only way for them to close on themselves is for them to loop back around outside the solenoid. Irregardless of this, if the magnetic...

Think of curl(E) as a line integral over an infinitesimally small loop. Thus curl(E) will be zero outside the solenoid because the sum of each of those infinitesimally small sides will equal to zero. Similarly you could deduce that curl(E) would be equal to zero over that infinitesimally small...

Just because curl(E) is zero doesn't mean that E is zero.

Another thing, take the line integral of E around a closed loop. But now have the loop off to the side of the solenoid. That line integral will equal to zero because the - and + contributions will cancel each other out. BUT even though the line integral of E is zero, that doesn't mean that E...

I think you're getting a little bit confused. Think of Ampere's law. A magnetic field curls around some current. Imagine that current is due to a wire. Now imagine you are calculating the magnetic field far away from the wire. You still have a magnetic field even though there is no current close...

The magnetic field lines outside the solenoid tend to much "further" spaced apart than inside the solenoid (i.e. the flux outside << flux inside)

Yes, see my post.

The B-field isn't really zero, just very small. But I don't think that's the point. Take the integral form of Faradays law: i.e. that the surface integral of dB/dt is equal to the line integral of E around a closed contour which bounds that surface. Imagine then drawing a closed loop around...

From an EM textbook (dealing with an above surface time varying magnetic field source): Primary field: Field artificially produced. Secondary field: Field produces by the charge/current created by the primary field. “Because air is so highly insulating in comparison to almost all in-situ...