- #1
Nikitin
- 735
- 27
Homework Statement
For two plane EM waves with identical amplitude, frequency, polarization and phase traveling in the directions of ##\hat{k_1}## and ##\hat{k_2}##, show that their average intensity is given by
##2I_0[1+\cos((\vec{k_2}-\vec{k_1}) \vec{r})]##
The Attempt at a Solution
Ugh, I've been struggling for an hour with this one. What am I to do? I tried adding the ponyting vectors, but I got an average intensity of 2I_0, which is obviously nonsense. What I can't understand, is what ##\vec{r}## actually is? I mean, according to the result I'm supposed to get, the average intensity can get as high as 4I_0 even if ##\vec{r}## is perpendicular to one of the ##\hat{k}##s!
Can somebody please show how to solve this problem?
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