"FrediFizzx" wrote in message
...
| "Franz Heymann" wrote in message
| ...
| |
| | "Jesse Mazer" wrote in message
| | ...
| [snip]
| | even though the
| | experiments to determine epsilon_0 and mu_0 have nothing to do with
| | light.
| |
| | No experiments have ever been done to determine the values of eps0 and
| | mu0.
|
| I think what he really meant was k_e in Coulomb's law and k_m in Ampere's
| law (the electric and magnetic constants).
|
| | They are artefacts necessary to define a certain set of units.
| | Such experiments are logically impossible, for the following reasons:
| |
| | mu0 is *defined* to be precisely 4* pi*10^-7
| | and eps0 is *defined* to make eps0*mu0 = c^-2
| | (and c, in turn, has a *defined* value, but we'll let that pass)
|
| The real SI magnetic constant of 2*10^-7 N/A^2 is simply the result of the
| definition of the ampere as a base unit. It was multiplied by an ad hoc
| constant of 2pi. That means that eps0 has an ad hoc value of 1/2pi in it.
| Eps0 = 1/4pi in gaussian cgs units. Take out the ad hoc constant then
| eps0*2pi = 1/2 in gaussian cgs. Which is consistent with what the
following
| link has to say if the magnetic constant is 1/c^2. k_e/k_m = c^2/2
|
| http://www.ee.surrey.ac.uk/Workshop/.../unit_systems/
|
| So what happened to this 1/2 for k_e in gaussian cgs units since k_m is
set
| to 1/c^2? This would mean that in natural units of hbar = c = 1, k_e
should
| be 1/2 and k_m should be 1. k_e = 1/2 got shoved into the product of q*Q
in
| Coulomb's law is what happened in gaussian cgs because they set it to 1.
So
| it seems that the gaussian cgs system is somewhat "*******ized". But the
| big question here then is what the HECK does this 1/2 represent? Well, I
| already told you what I think it represents.

Ok, I think I got this straightened out now. No problem. k_e =
1/(4pi*eps0) is the real SI electric constant. Eps0 has an ad hoc factor of
1/4pi in it. Not 1/2pi. Since k_e = 1 in gaussian units, then k_m = 2/c^2
which is easy to see at the following link,

http://scienceworld.wolfram.com/phys...llelWires.html

And the real SI magnetic constant is mu0/2pi. So the real equation goes
like this,

c^2/2 = (1/4pi*eps0)(2pi/mu0)

So there is no 1/2 factor. Which is good because that was totally messing
me up. The real ratio of the physical length of E_0 to wavelength is 1/2pi.
Not 1/2.

FrediFizzx