Power Irradiance Homework: Find Intensity

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The discussion focuses on solving a homework problem related to power irradiance, specifically finding intensity through the average value of the Poynting vector. Participants clarify that the intensity is equivalent to the mean value of the Poynting vector, with both having units of W/m². The relationship between the speed of light and the permittivity and permeability of free space is also mentioned, highlighting the equation c = 1/sqrt(ε0*μ0). The original poster seeks guidance on the next steps after establishing these concepts. Overall, the conversation emphasizes understanding the Poynting vector and its implications for wave intensity.
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Homework Statement


30idtmc.jpg
[/B]

Homework Equations



The Attempt at a Solution


I found the expression for the magnetic field, and then the Poynting vector.
2nu6e6u.jpg


If i find the intensity, that's the same as finding the average value of the Poynting vector, and the cos^2 disappears... Can you tell me what to do next?
Thank you.
 
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Bump Bump. Does anyone know what to do next?
 
OhNoYaDidn't said:
Bump Bump. Does anyone know what to do next?
Please observe the Forum Rule regarding bumping.

Bumping
Do not "bump" one of your threads to the top of a forum's thread list by posting a basically empty message to it, until at least 24 hours have passed since the latest post in the thread; and then do it only once per thread.​
 
OhNoYaDidn't said:

Homework Statement


30idtmc.jpg
[/B]

Homework Equations



The Attempt at a Solution


I found the expression for the magnetic field, and then the Poynting vector.
2nu6e6u.jpg


If i find the intensity, that's the same as finding the average value of the Poynting vector, and the cos^2 disappears... Can you tell me what to do next?
Thank you.
What does the Poynting vector tell you about the wave's intensity? What are it's units?

How is the speed of light, c, related to ε0 and μ0 ?
 
I wasn't aware of that rule, thank you for pointing it out.
The intensity is the mean value of the Poynting vector. The units of the Poynting vector are W.m^-2, the same for intensity..
I can use the retation c=1/sqrt(ε0*μ0), and therefore reducing 1/cε0 = sqrt(ε0/μ0). What should i do next?

Thanks for your reply.
 
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