[SI-LIST] Re: how EM wave propagates through space
- From: earl albin <earlalbin@xxxxxxxxx>
- To: Ihsan Erdin <erdinih@xxxxxxxxx>
- Date: Tue, 4 Oct 2011 09:18:05 -0700
Actually an electron doesn't really need a conducting media. For instance
when an electron traverses a shell, in particular when it goes to a lower
energy state and emits a photon of a wave length associated with that energy
difference, that emission is EM energy (LED).
But I like Vinod's answer, disturbance of energy, which is conservative.
That means the disturbed energy (photon/EM) travels and imparts energy into
some other form when it impacts. A photon striking an antenna and creating a
current. A photon striking steal and creating heat
On Tue, Oct 4, 2011 at 8:10 AM, Ihsan Erdin <erdinih@xxxxxxxxx> wrote:
> Vinod,
> Even if you want to avoid the equations, you should at least acknowledge
> the
> field concept and imagine a space permeated by the field lines. The wave
> propagation is simply the propagation of the disturbance (energy) which is
> generated by a moving charge in this field. The source of the disturbance
> (charge) doesn't have to be there for the energy to propagate just like a
> fault on the ocean floor could be thousands of miles away from the shores
> where tsunami hits.
>
> On Tue, Oct 4, 2011 at 10:38 AM, vinod ah <ah.vinod@xxxxxxxxx> wrote:
>
> > Hi All,
> > Can anyone please explain the EM wave movement in free space rather than
> > going into equations. It is very easy to quote Maxwell's equations &
> > complex
> > mathematical derivations to explain but physically how does the
> > wave propagate as we know that for electric field to exist there should
> be
> > a
> > charge and free space has no charge!!!.For magnetic field to exist the
> > charge should be in motion and if charge is only not there where is the
> > point of motion!!! If i am wrong do correct me.
> >
> > Regards
> > Vinod A H
> > EchoStar Corporation
> >
> > On Tue, Oct 4, 2011 at 7:52 PM, Ihsan Erdin <erdinih@xxxxxxxxx> wrote:
> >
> > > Shahbaz,
> > > A few corrections to your assumptions follow. First, the electric field
> > is
> > > due to the charge (electron) itself not its motion. The charge motion
> is
> > > attributed to the magnetic field but indeed magnetic field originates
> > from
> > > the spin properties of matter which is a more complex quantum effect.
> You
> > > can find a good presentation of this subject in the following portal
> > >
> > > http://en.wikipedia.org/wiki/Portal:Electromagnetism
> > >
> > > The second issue is that you don't need conductors for field
> propagation.
> > > EM
> > > fields will propagate in vacuum, as well. Maxwell-Ampere law relates
> the
> > > time varying electric field to the curl (rotation) of the magnetic
> field
> > > through displacement current. In other words, a time varying electric
> > field
> > > generates magnetic field. Maxwell-Faraday law, on the other hand states
> a
> > > time varying magnetic field is the source of electric field. The
> > > interleaved
> > > generation of the electric and magnetic fields from one another is the
> > > cause
> > > of energy propagation in the permeating field at the speed of light.
> > >
> > > Regards
> > >
> > > On Tue, Oct 4, 2011 at 5:38 AM, S A <shahbaz_assad@xxxxxxxxxxx> wrote:
> > >
> > > >
> > > >
> > > >
> > > >
> > > > Hi Experts,
> > > >
> > > > My question is related to propagation of EM waves.
> > > > As EM waves have electric field and magnetic field and as we know
> that
> > > > electric field is due to the motion of electrons and require some
> > > conducting
> > > > medium.But I am confused that how EM wave propagate through space.
> what
> > > > happens to the electric and magnetic field?
> > > > I am sorry my question is very basic. but what happens to the
> electric
> > > and
> > > > hence magnetic field in space and how these fields exists in space.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Thanks,
> > > > Shahbaz Assad
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
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> > > --
> > > Ihsan Erdin
> > >
> > >
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> --
> Ihsan Erdin
>
>
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