What Is the Rate of Energy Transfer for a 0.050T EM Wave?

AI Thread Summary
The discussion revolves around calculating the rate of energy transfer for an electromagnetic (EM) wave with a maximum magnetic field of 0.050T. Participants explore the relationship between the electric field and magnetic field using the equation B = E/c, leading to an electric field value of 1.5 x 10^7 V/m. The Poynting vector, which represents energy transfer, is introduced as S = (1/μ₀)(E)(B), although its relevance to the problem is debated. The breakdown of air at E = 3 x 10^6 V/m is mentioned, but its significance to the calculations is questioned. Overall, the conversation highlights the complexities of applying theoretical concepts to practical scenarios in electromagnetism.
lloyd21
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Homework Statement


It is fairly easy to produce a static magnetic field of 0.050T in the lab. If an EM wave could be produced with maximum magnetic field, Bo = 0.050T

a) what would be the rate of energy transfer (W/m2) ?

b) what would the corresponding maximum electric field be?

Note * Air "breaks down" at E = 3 x 10^6 V/m, that is sparks will jump across such a field.

Homework Equations


B= E / c
c = speed of light in vacuum

The Attempt at a Solution


0.050T (3.0 x 10^8 m/s) = 1.5 x 10^7 (electric field ?)
 
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lloyd21 said:
2. Homework Equations
What about (the 'microscopic' version of) Poynting's theorem?
 
Im not familiar with that?
 
S= (1/Mo)(E)(B) ?
whats the S, and why is there a not about the air break down
 
lloyd21 said:
S= (1/Mo)(E)(B) ?
whats the S, and why is there a not about the air break down
S is the Poynting vector, and it's a cross product of E and B. But look a bit further down and you will see an expression for energy density. I thought that would be relevant to the question. Of course, that form is for a vacuum. Maybe you need a variant for air.

I don't think the note about air breakdown is relevant to answering the question. More likely it is for understanding the inference of the answer.

Having said all that, I'm no expert in this area.
 
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