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Hi
I think they are in phase for a non-conducting medium - hence the
diagram. The wave equations for the electric and magnetic fields can be
written -
E(x) = E(0)sin(2pi/lambda)(vt-z)
and
H(x) = H(0)sin(2pi/lambda)(vt-z)
where v= velocity of the wave (for em waves in free space = c), t = time
travelled and it's all in the z direction.
A more detailed answer should leave you Poynting in the right
direction...(*)
> However, for the self-propagation of the photon package, the magnetic
> field vector, perpendicular to the electric field, is equally important.
> I have seen a drawing - I recall in Eisenberg's
> Physical Chemistry, that shows Electric and magnetic field vector
> at the maximum at the same point.
>
> If I look at the Maxwell equations, it appears however, that at the
> maximal change of H, induced E is largest, and at maximal change of E,
> the induced H. So should not H peak, when E goes though zero? This
> would create some 'selfinduction' or 'propagation'.
>
> Obviously something is wrong with my picture. Can anyone shed light
> on the phase relation between H and E in a wave packet? I did not find any
> other drawing or explicit explanation in any of my older (German) physics
> books,
> and I was never really hot on electrodynamics.
> Any references would be welcome.
>
> Cheers, br
* okay, I admit I looked it up in my copy of Pain's "Physics of vibrations
and waves".
Harry
--
Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC Centre, Hills
Road, Cambridge, CB2 2QH
