"lu6etj" wrote
...
On 7 jul, 16:55, "Szczepan Bialek" wrote:

This principle is used today to produce the light in the free electron
laser: http://en.wikipedia.org/wiki/File:FEL_principle.png

Yes, very interesting example (and device),

Respect to DC current EM radiation, In that time Richard bring an
interesting example of 20 kV electron rectilinear beam rendering a
frequency of 34.6 EHz, the calculus it was quite right, but that
frequency it is not EM waves radiated by electrons but a "matter wave'
frequency... (idem with car analogy = not charged and acelerated
cars :) do not radiates EM waves, but may have a matter wave
asociated to them).

Each waves are the matter waves. The speed is the particles mass dependent.
So in the wire the sound waves travel with the low speed (medium are ions),
and the electric waves (medium are the free electrons) with the extremally
high speed.

For these reasons IMHO I think -as Cecil do-: basic (undergraduated?)
physics books are very useful to helping us to better understand and
enjoy our ham topics.

For graduated is the field math only.
S*

73 - Miguel