On Jun 5, 9:42*am, Cecil Moore wrote:
On Jun 4, 7:19*pm, Keith Dysart wrote:

If, for all time,
the current or voltage is 0, then so is the energy flow.

You left out the word "net" again.

Not left out. No need to mention since this is the only energy
involved.

Indeed, there is zero *net* energy
flow in a pure standing wave. It is technically not a wave because it
doesn't transfer energy and momentum.

Certainly a standing wave is not a wave that transfers energy.

Keith, could you refresh my memory on those instantaneous power
equations that you once published. Given a forward wave and a
reflected wave, what was your equation for instantaneous power?

Choose a point on the line. Measure the instantaneous voltage and
current at that point. Multiply them together. You have the
instantaneous energy flow at that point and time. Integrate over
a full cycle (assuming a repetitive signal), divide by the period
and you have the average energy flow.

None
of my references consider EM standing wave instantaneous power to be
important enough to present a mathematical treatment of the subject.

Definitely not of interest for standing waves (which everyone agrees
are not really waves), but any decent text will derive
Pavg=Vrms*Irms*cos(theta) for sinusoids by doing exactly the steps
I mention above.

You are welcome.

....Keith