(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Show that in vacuum the magnitude of the momentum density

vector of a plane electromagnetic wave is equal to the energy density

divided by the speed of light, c.

2. Relevant equations

[itex]\vec{S}[/itex] = [itex]\vec{E}[/itex]x[itex]\vec{H}[/itex]

3. The attempt at a solution

This doesn't seem too hard if you know what a momentum density vector is, so if this should be in the introductory section I apologize but it is a hw question from an upper division course.

The only thing I'm really looking for is how to find/ what is a momentum density vector. I have no idea how to go about finding it.

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# Homework Help: Momentum density vector of a plane em wave

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