Power Irradiance Homework: Find Intensity

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Homework Help Overview

The discussion revolves around a physics problem related to power irradiance and intensity, specifically focusing on the Poynting vector and its implications for wave intensity.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between the Poynting vector and intensity, with one participant noting that finding intensity involves calculating the average value of the Poynting vector. Questions are raised about the next steps in the process and the implications of the Poynting vector's units.

Discussion Status

Some participants have provided insights regarding the relationship between the Poynting vector and intensity, as well as the units involved. However, there is no explicit consensus on the next steps to take in the problem-solving process, and multiple interpretations are being explored.

Contextual Notes

Participants are navigating forum rules regarding posting frequency, and there are references to specific equations and relationships in electromagnetism, such as the speed of light in relation to ε0 and μ0.

OhNoYaDidn't
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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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