First of all I have to say that translating specific words from native language to english, is not easy. So I hope that you realize what is going on:

What did I do wrong ?

(Traveling waves from: Wave - Wikipedia, the free encyclopedia ).

Printable View

- Jun 8th 2007, 10:34 AMtotalnewbieElectromagnetic wave equation
First of all I have to say that translating specific words from native language to english, is not easy. So I hope that you realize what is going on:

What did I do wrong ?

(Traveling waves from: Wave - Wikipedia, the free encyclopedia ). - Jun 8th 2007, 06:08 PMPterid
OK. First, we should just state the form of the 'wave equations'. These have a lot of interesting physics behind them, but for now we'll just state them!

Say the light wave travelling in the -direction, in free space. Then, say the wave is polarised, so the electric field is in the -direction. Then the only non-zero components of the fields are and :

Now, an explanation of the symbols I've used:- is the
*wavenumber*(or*wavevector*) of the wave. It's defined by , where is the wavelength. - is the
*angular frequency*of the wave. It has units of "radians per second", and relates to the 'true' frequency by . - is the speed of light.

and so you can calculate

.

( is a unit, the*tesla*.)

Put these into the expressions above, and ignoring the units, you get:

;

.

- - -

Your answers are written slightly diffierently: they have a minus sign, . This doesn't matter. However, I seem to have a different answer for (I don't know why!)

Also, the form used in Wikipedia has an "extra" phase factor ; I have made . You can do this just by choosing the*origin*of your coordinates in the right place! - is the
- Jun 9th 2007, 11:34 AMtotalnewbie
- Jun 9th 2007, 04:49 PMPterid
Well, yes, but the relation is consistent with a vacuum - and if the problem were "set" in a medium, you would expect the question to tell you something about the medium...

If I were a more arrogant kind of person, I might suggest that the answers had a typo in! :o