Momentum density vector of a plane em wave

  • Thread starter aftershock
  • Start date
  • #1
aftershock
110
0

Homework Statement



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.

Homework Equations



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

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.
 

Answers and Replies

  • #2
dextercioby
Science Advisor
Homework Helper
Insights Author
13,242
1,022
Do you know how the 16 components of the energy-momentum tensor look like ?
 

Suggested for: Momentum density vector of a plane em wave

Replies
0
Views
412
  • Last Post
Replies
1
Views
804
  • Last Post
Replies
0
Views
195
Replies
3
Views
398
Replies
2
Views
386
Replies
9
Views
686
Replies
3
Views
637
Replies
3
Views
568
  • Last Post
Replies
2
Views
213
Top