All Questions
321
questions
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2
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123
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Diffraction when the wavefront is not parallel to the plane
I am studying Feynman's chapter on the origin of the index of the refractive index (see this link).
If I am not mistaken, what he does is to prove that when a wave enters a medium (modelled as a ...
- 507
1
vote
0
answers
27
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What actually happens when light goes into a waveguide?
I have only dealt with a rudimentary theoretical treatment of how light propagates inside a waveguide, such as those available in Griffiths.
One thing bugging me is that I still do not know how ...
- 692
5
votes
3
answers
2k
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Is it possible to get an electromagnetic wave equation if the speed of light were infinite?
In an old question: How would night sky look like if the speed of light was infinite? the best answer was voted down to negative credits.
I cannot understand why. From Maxwell's equations, we derive ...
- 59
0
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0
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32
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Electromagnetic Field in a 3D Cavity with Lossy Boundary
I would like to find the electric and magnetic fields inside a cubic cavity with a lossy boundary (i.e. NOT a perfect conductor). I assume that the interior of the cavity is filled with a homogeneous ...
- 1
1
vote
0
answers
16
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Why is the intensity of a beam of light the squared magnitude of the phasor and not just the squared magnitude of the real part?
I'm learning about phasors and light intensity and there are two conflicting things I've been told that I can't reconcile.
Firstly I've been told that a phasor $e^{-ikz+i\phi}$ is a mathematical way ...
- 531
1
vote
1
answer
51
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Would we be able to see the superposition of two X-rays where the frequency of the modulation matches visible light?
Suppose I had the superposition of two electromagnetic waves whose angular frequency was in the X-ray region. Together they form a composite made of a carrier wave and a modulation wave where the ...
- 531
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2
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102
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Why In an electromagnetic wave both electric and magnetic waves are in sync and perpendeculare? if one makes the other shouldnt there be a delay? [closed]
Why are electric and magnetic waves in phase if one induces the other? Shouldn't there be a delay, similar to how potential energy converts to kinetic energy and vice versa? Additionally, why are ...
- 21
7
votes
5
answers
14k
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Light waves can't have a wavelength
The wave nature of light comes from Maxwell's equations. More precisely, the two wave equations that come from them:
$$\Delta\vec{E}=\mu\varepsilon \frac{\partial^2\vec{E}}{\partial t^2}\\
\Delta\vec{...
- 267
1
vote
1
answer
31
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Effect of incident angle on wavelength of transmitted wave for normal polarisation?
In my electrodynamcis assignment I'm being asked to derive the wavelength of a normally polarised wave transmitted through a glass/air interface as a function of $n_1$ (the refractive index of the ...
- 11
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0
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23
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"The Fields of a Point Charge in Uniform Motion 1" in Zangwill
In Chapter 20 of Zangwill's Modern Electrodynamics, Application 20.1 the electromagnetic fields for a point charge in uniform motion (velocity $\textbf{v} = v \hat{z}$) along the z-axis is derived. ...
- 954
2
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44
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Understanding Green's Function Derivation for Inhomogeneous Wave Equation
I am currently reading through Zangwill's Modern Electrodynamics. In Chapter 20, Zangwill derives the Green's function for the wave equation
$$[\nabla^2 - \frac{1}{c^2}\frac{\partial^2}{\partial t^2}]\...
- 954
0
votes
2
answers
53
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Are all recursive interactions between electric and magnetic fields always orthogonal to each other?
ecursively, this implies that changes in the electric field generate the magnetic field, and vice versa, akin to the plane wave solution resulting from specific boundary conditions intentionally ...
- 21
0
votes
1
answer
56
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Can the magnitude of the electric field or magnetic field in a plane electromagnetic wave be equal to zero?
I have tried reading related questions on here, but I have not found what I perceive to be my question nor the answer I seek. Every place I look (textbooks, here, Quora, etc...) indicates that $E_0/...
- 9
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0
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30
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Polarization of electric field and its effect on the Poynting vector
To preface, I've little experience with optics. This is a very use-case specific project I'm undertaking. So, if there are any improvements in my method, I'd appreciate it!
I'm working with the vector ...
0
votes
1
answer
41
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Is amplitude measured from the electric or magnetic fields of a wave?
When you measure amplitude, does that refer to the electric portion of the electromagnetic field, or does it refer to the magnetic portion? Or is an average of the two?
Another question is, are the ...
- 187