What is the meaning of the Poynting Vector?

Question

Maxwell theory of light

Answer 1

The Poynting vector is commonly given (for a linear medium) as:

S = E x H
where E is the electric field, H is the electric field.

This is a vector denoting the direction of energy flow (the magnitude is the power per unit area through a surface normal to the vector).

Answer 2

Hi. One of the neat points about Yahoo Answers is that even if you know nothing about a question you can get curious about it. I looked Poynting Vector up and, as you probably know, it applies to electromagnetic relationships to surfaces. So I learned something. (This makes me happy.) But I would point out the relationship between the vector and the "skin effect" in radio. As an amateur radio operator I have learned how this effect, which causes all RF current in an antenna to travel ONLY on the outside surface of the conductor, is caused by the natural repulsion of electron to other electrons. They "push" themselves to the outer surface. Thanks for giving my curiosity a tickle.