All Questions
55
questions
1
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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
0
votes
1
answer
66
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Direction of propogation of a EMW [closed]
If let say i have an EMW given by- (Note the difference between $k$ and K)
B(x,y,z)=$B_0sin[(x+y)\frac{K}{√2}+wt]\hat k$
i got confused in 2 different outcomes when i wanted to find out the direction ...
- 367
1
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0
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72
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Electromagnetic waves in medium with strange polarization vector
I have an exercise in Electromagnetic waves, basically to find the refractive index of a wave in a medium with polarization $\mathbf{P}=\alpha \nabla \times \mathbf{E}$. I used the Maxwell equations ...
- 147
1
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0
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54
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How is $E×B$ zero? [closed]
I was reading Feynman lectures vol. 2 pg no. 291. There I found the general solution of one dimensional planar waves along $x$ direction. My question is the when I apply dot product on $E$ and $B$ ...
- 157
0
votes
1
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157
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Unpolarized light incidence
A beam of unpolarized light carries 2000W/m2 down onto an air–plastic interface. It is found that of the light reflected at the interface 300W/m2 is polarized with its $E$-field perpendicular to the ...
- 980
1
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0
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43
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When and how will charged oscillating pendulum in vacuum and Earth gravity stop?
Let's say there is a positively charged metallic sphere hanging on a thread in Earth's gravity and in vacuum. There is no electric field (except for the field from the sphere itself), no friction etc. ...
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0
votes
1
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223
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Electric field strength $d$km from a television transmitter of power $P$kW, assuming isotropic radiation
I think I need to use the Poynting vector to do this, as it is equal to the power per unit area flowing through a surface.
At a distance $d$km from the transmitter, the surface will have a surface ...
- 75
0
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1
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320
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Can both magnetic and electric fields induce current from an EM wave?
I was reviewing a homework problem I completed for class, but I saw different explanation that contradict each other.
My teacher says that this position for the waves is optimal for maximum induced ...
1
vote
0
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79
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Proof $\Delta \vec{E} = \frac{1}{c^2} \frac{\partial ^2\vec{E}}{\partial t^2}$ [closed]
Here's what I'm doing, but I'm not sure if this is correct.
Furthermore, I think $c^2$ is the speed of light, however is $c^2 = (\mu_0\epsilon_0)^{-1}$ as follow?
$$\nabla \times (\nabla \times \vec{...
- 29
-1
votes
1
answer
136
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Radiating quadrupole [closed]
I'm trying to solve the following problem.
Two charges $+q$ are located along the $z$ axis at $z=\pm a \sin \omega t$. Determine the lowest non-vanishing multipole moments, the vector potential and ...
- 685
-1
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1
answer
179
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Electromagnetics - how to choose a proper normal vector? [closed]
In D.K.Cheng's equation 8-29 he makes the following correlation between the magnetic field intensity $\mathbf{H}$ and the electric field intensity $\mathbf{E}$ in an electromagnetic wave.
Where $\eta$...
- 246
1
vote
0
answers
16
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When do travelling (accelerating) charged particles emit radiation in their direction of travel and when perpendicular to their velocity? [closed]
I have read numerous things saying that a travelling charged particle emits radiation primarily in a cone in the direction of travel, and other places say the radiation is emitted and polarized in an ...
- 4,515
0
votes
1
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86
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Troubles verifying $\langle \omega \rangle = \frac{1}{2}\epsilon \epsilon_0 |\vec{E}_0|^2$
I'm trying to prove that the time average of the energy density $\omega$ is equivalent to
$$\langle \omega \rangle = \frac{1}{2}\epsilon \epsilon_0 \|\vec{E}_0\|^2$$
for a plane EMW. My approach is to ...
- 254
-1
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1
answer
361
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Calculating the Poynting vector for a line charge moving along its length [closed]
The problem reads:
An infinitely long thin wire carrying a uniform linear static charge density $\lambda$ is placed along the z-axis. The wire is set into motion along its length with a uniform ...
- 133
2
votes
1
answer
1k
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Confusion even over such a simple application of the Right-hand rule to determine direction of magnetic field
After reading this question on this site I learned that the direction of the magnetic field is given by $\boldsymbol{B}=\frac{1}{\omega}\boldsymbol{k}\times \boldsymbol{E}$
The left diagram below is a ...
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