Electromagnetic Power and Poynting — Lesson 13

[carmelpule]

In some most videos, including this series, a plane wave is normally shown polarised, moving along the z axis as an E and B wave in space quadrature.The fact that the E and B components of an E/M wave are shown in phase, then this means that due to the " in phase" amplitudes of the B and E waves, then the Power Poynting vector is not a constant, and it pulsates, even reaching zero when the Magnitude of E and B are both zero at the same time. However in reality, in a lossless medium the Poynting Power vector of an E/M wave is constant and is merely transferred from the E to B field without any losses. This seems to suggest that diagrams representing the E/B waves shown in space quadrature and in phase along the transmitted direction needs further consideration, How could one explain this to newcomers to the subject? I believe there should be a pi/2 angle somewhere! and that will make the tortal power being exchanged between the E and B field as it propagates out a " rotating" constant. In all oscillating systems like pendulums and LC circuits it is always an exchange of energy while the total energy remains constant, This characteristic phenomena should appear in any E/M diagram we show

[yongtuition]

I think Richard Feynman mistakenly applied the Poynting theorem in static E&M fields. What do you think?

[scarlettirons]

Great video but the notation at 0:45 is slightly confusing - as I think epsilon is used for an E and epsilon and I think the last letter is a J but looks like a d. Other than that thanks so much - these videos are saving my degree!

[yongtuition]

0:48 You forgot adding dV on the right hand side.

[mallakbasheersyed]

mam can u explain how the avg power is equal to 2nd equation at time 1:55 ...i want the proof pls

[DollyCleveland-lf]

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