Re: electrical units

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Philip,
            I'm sure this could end up being way OT but I'll see if
the moderator will let it pass ;)

On 4 Feb 2004, at 11:48, Tesla list wrote:

 > Original poster: "Philip Brinkman" <peeceebee-at-mindspring-dot-com>
 >
 > Getting deep in here :)
 >    Seriously, though, I always wondered, what is electricity, really?
 >    I have
 > heard that it travels at the speed of light...but that is impossible
 > if I understand Einstein's theories...is it an electron mooving from
 > point a to b? Electrons are  particles, even the Fermi accelerator
 > can't  get an electron to moove that fast, I just don't see how
 > electricity can moove that fast. - Philosophical Phil Brinkman

It is not electron speed which equals c, it is the accompanying
influence (the electric and magnetic fields) which do. Even that
needs to be qualified since that influence is medium-dependent i.e.
the best you can do is c in a vacuum where uo and eo are limiting
values - in a transmission line for example, both the inductive and
capacitive components are larger causing the propagation velocity to
fall below c. A Tesla Coil resonator is deliberately designed to to
boost these components enormously within a relatively small volume.
You may hear the resonator referred to as a "slow-wave" resonator in
some quarters. You might imagine a wavefront advancing along the
wire, spiralling its way to the top while picturing a wavefront
advancing slowly along the length of the coil.

      You might like to consider this (a real can of worms but within
the world of transmission lines): If you have a battery, resistor and
perfect pair of wires (no resistance), connect the resistor across
one end of the pair of wires and then connect the battery across the
other end, does the current instantly become V/R? Suppose the wire
is, say, 1 light-second long. At the instant the battery is hooked to
the piece of wire, it has "no idea" what the load at the far end
might actually be. What is the initial current? It may be V/R by
sheer luck but is most unlikely to be so. I'm asking this
rhetorically since in order to answer the question, one needs to know
the *characteristics* of the wire line.

     Finally, it is not reasonable to ask "what is electricity?" or
anything else of a fundamental nature. We can only describe the
characteristics of these things in terms of some object or phenomena
in the visible macroscopic world we experience. Such modelling can
only amount to an approximation and partial description at best. The
answer is that "electricity is electricity", "electrons are
electrons" and so on. A good example is the old question of whether
light is a particle or wave. Depending on how one looks at it, it
could be seen as possessing particulate properties, wave properties,
electromagnetic properties and so on. That is not what light is -
it's just some of the ways in which we might see it behaving.

      The view I've just presented is of course totally open to
debate, agreement and disagreement (which is why I called it a can of
worms).

Malcolm