The poynting-vector tag has no wiki summary.
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Using the Poynting Vector in Coaxial Cables for Power
Why is it that we can use the Poynting Vector to find the power dissipated in a Coaxial Cable? Unlike the situation with light, where the c makes sense, inside the coaxial cable I see no reason why ...
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1answer
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Derivation of the Poynting Vector without the Poynting Theorem
My professor worked out the Poynting Vector without using the Poynting Theorem-I can't remember how. I can't seem to figure out where the cross product would come in.
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Where Is the mechanical energy flow in Poynting's theorem?
Poynting's theorem is usually interpreted as the statement of the conservation of energy, where the change in mechanical and electromagnetic energy within the volume equals the flow of electromagnetic ...
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Absorbance by using Poynting vector
How should I compute the amount of energy of an EM wave absorbed in the material?
Can I just use the divergence times the Poynting vector?
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3answers
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Surface integral of Poynting vector around static sources
Consider fields $\rho \left( \vec{r} \right)$, $\vec{J} \left( \vec{r} \right)$, $\vec{E} \left( \vec{r} \right)$ and $\vec{B} \left( \vec{r} \right)$ in $\mathbb{R}^3$, with their usual meaning as ...
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Irradiance (or intensity) of an electromagnetic wave
Is the irradiance (or intensity) of an electromagnetic wave given by
\begin{equation}
I = \left<\|\mathbf{S}\|\right>_{T}
\end{equation}
or by
\begin{equation}
I = ...
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413 views
Poynting vector of a wire between capacitors
A capacitor made of two circular plates of radius $L$ separated by $d$, initially the plates carry $\pm$ Q charge.
Then a wire of resistance R is placed between them, how do I go about deriving a ...
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377 views
Deriving the Poynting Theorem
I am trying to derive the Poynting theorem. So far, I've only been able to narrow down which equations I think I'll need to do so. These are the equations:
Maxwell's Equations:
$$
\nabla\times{\bf E} ...
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213 views
electromagnetics : intrinsic impedance and poynting vector
I know that 1/2 of the real part of the complex poynting vector gives the average power flow per unit area. But what is the significance of its imaginary part ?
What is the significance of the ...
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1answer
622 views
Computing the Poynting vector?
Approaching the following problem:
A plane monochromatic electromagnetic wave with wavelength $\lambda = 2.0 cm$,
propagates through a vacuum. Its magnetic field is described by $
> \vec{B} = ...
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2answers
102 views
X-ray diffraction from crystals and time-averaging
To calculate the elastically scattered intensity of x-rays from crystals, one classically considers scattering from a free electron first and then one sums up the scattered em-fields of all electrons ...
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102 views
Intensity of unpolarized light
If the electromagnetic field of an unpolarized plane wave is written as
$$\bar{E}(t,\bar{x})=(\bar{E}_{0x}+\bar{E}_{0y}e^{i\delta(t)})e^{i(\bar{k}\bar{x}-\omega t)}$$
...
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Conservation of Energy and the Poynting Theorem
Conservation of energy in an electrical circuit can be expressed by Ampere's law $$\nabla \times \textbf{B} = \mu_o
\textbf{J} + \epsilon_o \mu_o \frac {\partial \textbf{E}} {\partial t}$$ when ...
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2answers
382 views
Does a nonzero Poynting vector mean that there is propagation of energy?
I don't know how this "paradox" can be solved. I'm given the following system: A permanent magnet with a magnetic field given by ($\hat{a}$ are unit vectors in the x and y directions)
...
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323 views
Is there something like the Poynting vector for hydraulic circuits?
The Poynting vector is a representation of the energy flux in electromagnetics, showing the amount and direction of power flow at different points in space. In electric circuits, the energy is not ...
