[SI-LIST] Re: how EM wave propagates through space
- From: Paglia Frank-B37323 <B37323@xxxxxxxxxxxxx>
- To: vinod ah <ah.vinod@xxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Tue, 4 Oct 2011 15:04:31 +0000
Vinod,
If you take a little bit of time to understand the equations then it makes
perfect sense. While it is true that an electric charge creates an electric
field, it is not the only why electric fields are created.
Basically what happens is this. A changing magnetic field creates a changing
electric field and a changing electric field creates a changing magnetic field.
These fields can propagate in free space, which as you said has no charge.
I suggest looking at A Student's Guide to Maxwell's Equations by Dan Fleisch.
He does a very good job explaining Maxwell, math and all, and helps you
understand in words what the equations are saying. Unlike some of the undergrad
texts it's a short book and he even has podcasts of him reading the text on his
website.
Just like anything that is worthwhile, EM takes some effort.
Best Regards,
Frank Paglia
Freescale Semiconductor, Austin, Texas
Packaging Solutions Development
Email: frank.paglia@xxxxxxxxxxxxx
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of vinod ah
Sent: Tuesday, October 04, 2011 9:38 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: how EM wave propagates through space
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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