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Old October 3rd 06, 06:32 PM posted to rec.radio.amateur.antenna
Cecil Moore Cecil Moore is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,614
Default Where Does the Power Go?

Richard Clark wrote:
Gene Fuller wrote:

reversing momentum


Imagine the G forces of that for an infinitesmal 1/10¹² second or so.


The pressure of such a momentum change can be calculated.
From "Optics", by Hecht, 4th edition, page 57:
"When the surface under illumination is *perfectly
reflecting*, the beam that entered with a velocity
of +c will emerge with a velocity of -c. This
corresponds to twice the change in momentum that
occurs on absorption, and hence,"

Pressure of a absorbed wave = S(t)/c

Pressure of a reflected wave = 2*S(t)/c
--
73, Cecil http://www.w5dxp.com