All Questions
8
questions
1
vote
2
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71
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$\vec{E}$-field in toroidal polarized dielectric
In an electrostatic situation, imagine a dielectric torus that is permanently polarized with polarization given by:
$\vec{P} = P(r, z) \hat{\phi}$
(Here cylindrical coordinates are used with the $z$-...
- 21
1
vote
1
answer
53
views
The intepretation of $d$ in $p=qd$
In Griffiths Example 4.1, the author derived the polarizability of a uniformly charged spherical cloud with radius $a$. For an external field $E$, the electron cloud will shift to the left with a ...
- 123
1
vote
2
answers
732
views
What does "weak-field limit" mean when it refer to dipole and atomic polarization?
In Griffiths' book, Introduction to Electrodynamics 3rd, problem 4.3,it requires me to find the condition on ρ(r) such that equation $p = αE$ will hold in the weak-field limit. The answer gives $ρ（r）=...
- 13
0
votes
0
answers
20
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How to interpret bound charges geometrically?
Conceptually, it makes sense to say that when there is an electric field along $E=E\hat{n}$, then given a polarization $P$, the amount that $P$ aligns with the electric field is simply the dot product ...
2
votes
1
answer
122
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Integrand discontinuity of surface integral of electric field of dielectrics
I am reading an article here on dielectrics
Equation $(4.10)$ is:
$$\Phi(\mathbf{r})=\dfrac{1}{4\pi \epsilon_0}\int_{V} \dfrac{d^3r'}{|\mathbf{r}-\mathbf{r'}|} [\rho (\mathbf{r'})\ -\nabla'.\mathbf{...
- 31
0
votes
2
answers
251
views
Question about Optical tweezers working principle
Why do particles on the periphery of the laser beam in optical tweezers apparatus drift to the center of the beam? What force pattern causes this pull to the center?
- 107
-3
votes
4
answers
3k
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About polarisation vectors and tensors [duplicate]
I don't understand the concept of tensors. Can anyone explain the relation between polarization vectors and tensors?
- 9
3
votes
2
answers
429
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What makes an insulator good for polarizing?
Water in an electric field become polarized easily, since the natural dipoles twist and turn to align with the field.
In non-polar insulating materials, a redistribution of charge can happen in the ...
- 51.4k