On Jan 11, 6:56*pm, Cecil Moore wrote:
On Jan 11, 5:03 pm, Keith Dysart wrote:

I suggest that since the current at the middle of the line
is always 0, the power is always 0 and therefore no energy
crosses the middle. While tracking mixed energy is difficult,
when no energy crosses a boundary it seems easy to keep the
energy on each side of the boundary separate.

Of course, what you say is only true for net energy. If we have a
forward Poynting vector of 100 watts and a reflected Poynting vector
of 100 watts, no net energy is flowing at any point.

You don't need Poynting vectors to realize that when
the instantaneous power is always 0, no energy is flowing.
And when the instantaneous power is always 0, it is
unnecessary to integrate and average to compute the
net energy flow, because no energy is flowing at all.

And if by your response you really do mean that energy
can be flowing when the instantaneous power is always 0,
please be direct and say so.

But then you will have to come up with a new definition
of instantaneous power for it can not be that it is
the rate of energy transfer if energy is flowing when
the instantaneous power is zero.

...Keith