A nit picky point concerning the place where (in an otherwise fine post)
Hugh Logan wrote:
... . The minus sign in Faraday's law comes from Lenz's law. ...
Actually, this is not necessarily the case. The sign in Faraday's law is
an arbitrary matter of convention. *But* once that convention is
settled on, then the sign relating the source (current) term to the
curl(B) in Ampere's law has the *opposite* convention as is chosen in
Faraday's law. Lenz's law only requires that the relative corresponding
signs in these two laws be opposite of each other. (If we choose Faraday's
law to have a + sign then Ampere's law must have a corresponding - sign &
vise versa.)