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Questions tagged [dielectric]

This tag is for questions relating to a non-conducting material called dielectric (or dielectric material). Dielectrics are very much important to explain various phenomena in various fields of physics like solid-state physics, optics, electronics, cell biophysics, etc.

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A capacitor partially filled with dielectric [closed]

Assume a parallel plate capacitor that was charged up to $Q_0$ from a source $U_0$ and then disconnected from the voltage source. The plates have an area $A$ and the distance between the plates is $d$....
Ilia's user avatar
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3 answers
65 views

Do conductors have bound charges?

In Griffiths, the total charge density of a dielectric is: $\rho$ =$\rho_b +\rho_f$. I have several questions: Can the total charge density of a conductor be written as the equation above? Do the ...
Felix wong's user avatar
2 votes
1 answer
27 views

Energy in Dielectric Medium as a Sea of Dipoles

Simply, why is the energy density in a dielectric medium = $\frac{1}{2}K\epsilon_oE^2$ where K is the dielectric constant of the dielectric medium? Working proof Consider a capacitor that is charged ...
Kayen Jain's user avatar
-1 votes
0 answers
16 views

Parallel plate capacitors with dielectrics [closed]

I was studying capacitors with dielectrics ,where my teacher gave one example for us to solve between the parallel plate capacitor there is dielectric which is further divided into four dielectrics ,...
Kushagra Mishra's user avatar
-1 votes
0 answers
27 views

What is dielectric constant of conductor if it is connected to battery as the electric field will generate in conductor does it still be infinite? [closed]

as we calculate dielectric constant of conductor saying Eext/Eext-Einduced = 0 but as inside conductor electric field net would be not equal to zero. `
Mayur Namdev's user avatar
0 votes
3 answers
32 views

Electric field at a point due to dielectric inserted in between a parallel plate capacitor [closed]

Here, I have a parallel plate capacitor with each plate having surface charge density $\sigma$. A dielectric of dielectric constant $K$, is inserted partially between the two plates. What would be the ...
NPC's user avatar
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1 vote
1 answer
54 views

Permittivity real and imaginary parts with similar value possible?

Here's the context; I'm studying biological tissues that are supposed to behave like dielectrics. Using the modified cole-cole equation for theoretical predictions: $$\tilde{\varepsilon}_r (\omega )= \...
Laurier's user avatar
  • 189
0 votes
1 answer
62 views

Understanding dielectrics on the basis of induced charge and energy density

Simply, why is the energy density in a dielectric medium = $\frac{1}{2} K \epsilon_o E^2$? For a simple case such as that of a capacitor with a dielectric medium inside it, to find the magnitude of ...
Kayen Jain's user avatar
0 votes
0 answers
36 views

Displacement current and magnetic field in capacitor with dielectric

I have a capacitor with round plates of radius $r_{2}$ kept at a distance $d$, with a voltage $V\left(t\right) = V_{0} \cos \left(\omega t\right).$ Inside, there is cylindrical material with a certain ...
sofia atzeni's user avatar
0 votes
0 answers
11 views

Difference between polarization angle and poling angle in piezoelectric material

I was reading the research article: Demonstration of optimizing piezoelectric polarization in the design of a flextensional actuator, where I had confusion differentiating between poling angle, which ...
user134613's user avatar
0 votes
3 answers
100 views

What is the net macroscopic electric field at any point inside a dielectric?

This question is based on section 4.2.3 of Introduction to Electrodynamics by David J. Griffiths (Third Edition). Consider a point $\vec{r}$ inside a dielectric where we are interested in finding the ...
Solidification's user avatar
2 votes
1 answer
89 views

Confusion on the definition of dielectric permittivity

I don't understand how we're defining the dielectric permittivity, sometimes it's defined as the ability of the material to resist the electric field and sometimes as the ability to permit the ...
Manish Parmar's user avatar
0 votes
0 answers
26 views

Is the capacitance obtained using the RC circuit equation the correct value?

To find the dielectric constant of the dielectric according to frequency, an RC circuit was constructed and the capacitance was calculated using the RC circuit equation using the voltage applied to R, ...
user376710's user avatar
3 votes
1 answer
61 views

Are superinsulators perfect dielectrics?

In Wikipedia its stated: "The phenomenon of superinsulation can be regarded as an exact dual to superconductivity." I understand that superinsulators are terrible conductors. But its not ...
Sidharth Ghoshal's user avatar
2 votes
1 answer
40 views

Bound Charges in Polarized Material

I'm currently working my way through chapter 4 of Griffith's Introduction to Electrodynamics (4th ed) and I ran into an issue with his notation. In chapter 4 sectin two, when calculating the electric ...
ReggiePlasmaQs's user avatar
1 vote
0 answers
95 views

What step is missing from this transformation of the Clausius-Mossotti relation into the Garnett-Maxwell equation?

When deriving the Maxwell-Garnett equation for composite systems (host material with dielectric particles disposed in it), the steps generally taken are Step 1) Equate the Clausius-Mossotti equation ...
user7077252's user avatar
2 votes
2 answers
45 views

How should I calculate the TE and TM modes on an anisotropic/uniaxial slab waveguide?

I want to find the equations governing the TE and TM modes on the following three-layered slab waveguide: I know how to use the Helmholtz equation and solve for the boundary conditions on normal ...
Guilherme Mendonça's user avatar
0 votes
0 answers
32 views

How is the local field in a dielectric material calculated?

I have read in different sources (text, video, amongst others) that the local field in a dielectric material placed within a capacitor can be easily calculated as the sum of 4 electric fields: $E_{...
user7077252's user avatar
0 votes
2 answers
47 views

Effect on a capacitor due to a dielectric

Why does the effect of a dielectric fully inserted between a parallel plate capacitor differ when the capacitor is connected to a battery source and when it is not? When a charged capacitor is not ...
Mel's user avatar
  • 133
1 vote
2 answers
28 views

Surface Charge Density At Boundary Between Vacuum And Linear Dielectric Within A Capacitor

In problem 4.19(b) from 'Introduction to Electrodynamics (Fifth edition)' By David J. Griffiths, we are given a capacitor (having its plates maintained at a constant potential difference V) with half ...
Kvn's user avatar
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1 answer
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Why is there attenuation or amplification of the electric field depending on the sign of angle?(Maxwell's equations in free space)

If you solve Maxwell's equations in free space for a complex $\epsilon$ you get this equation: $\triangledown^{2}E = -\mu \left |\epsilon\right |e^{i\phi}\omega^{2}E$. Compared to the equation when $\...
ElectronicsBeginner's user avatar
0 votes
2 answers
62 views

Total charge on a polarized neutral dielectric

I'm going through Griffith's EM book right now and from problem 4.14 we can see that the total charge on a polarized neutral dielectric is 0 (since it is neutral) the polarization may move around some ...
mastershooter77's user avatar
0 votes
0 answers
48 views

Can a material have zero free charge density while having non-zero conductivity?

I solved this problem where a lossy dielectric (conductivity: non-zero constant, permittivity: non-zero constant) is placed between two plates. I found that the magnitude of $E$ is constant since divJ ...
Mathematics 22C's user avatar
1 vote
0 answers
17 views

Is there simple harmonic motion when a dielectric longer than the capacitor is inserted into the capacitor? [duplicate]

I’m trying to understand the mechanics of a dielectric being inserted into a parallel-plate capacitor. Suppose I have a parallel-plate capacitor with plate separation d and a dielectric slab of length ...
Sai Charan Petchetti's user avatar
0 votes
2 answers
34 views

For a plane isolated capacitor with a dielectric slab partially introduced inside it, what's indpendent of the medium? $\mathbf E$ or $\mathbf D$?

Say we have an isolated capacitor with charge $Q$ and a dielectric slab, $\varepsilon_r$, partially introduced between the capacitor's plates, then, I'd say the displacement vector should be the same ...
Conreu's user avatar
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1 vote
2 answers
85 views

Charged plate between two different dielectrics

Imagine a charged plate, placed in between two DIFFERENT dielectrics of susceptibilities $\chi _1\:and\: \chi _2$ . From Gauss's law, We can conclude that the sum of the magnitude of the electric ...
CuSO4 NaOH's user avatar
0 votes
1 answer
52 views

Why does capacitance depend on medium?

Capacitance does not depend on charge or the potential difference due to it fundamentally being a constant which we have defined. I only have trouble understanding why does it then change if we change ...
Maanit's user avatar
  • 11
0 votes
1 answer
60 views

Why the dielectric permitivity matrix of lossless media is symmetric?

I am studying optics and I met a strange statement in the section 2.3.4 (page 34) of Fundamentals of Nonlinear Optics by Peter E. Powers and Joseph W. Haus. The relationship between $\vec{D},\ \vec{E}$...
Hsu Bill's user avatar
  • 388
1 vote
0 answers
40 views

Value of permittivity inside an atom

As we know, the permittivity of free space physically measures how dense an electric field can form in response to electric charges in free space. I have the following 2 questions: What will be the ...
Curiosity_killing_me's user avatar
0 votes
0 answers
36 views

Is there any electronic devices that maintain charged state?

I want to know how to make electronic devices that are continuously charged to + or - state on which surface when voltage is applied to utilize the dielectric polarization property, or if there are ...
SungJin Park's user avatar
0 votes
3 answers
96 views

Insertion of dielectric inside capacitor when capacitor is connected to a battery

When a capacitor is connected to an external voltage and a dielectric is inserted slowly across the plates, the energy of the capacitor increases. The energy preciously is $CV^2/2$ and after the ...
Bhishm Tahiliani's user avatar
2 votes
2 answers
378 views

Dielectric and dipole

When a molecule of a dielectric material is placed in an electric field, the molecule acquires an electric dipole moment. Why?
Sam Tunkaho's user avatar
0 votes
0 answers
44 views

Identifying symmetries of rank 2 tensors

Let's say I have a material with permittivity tensor: $$ \epsilon_1 = \begin{pmatrix} \epsilon_{xx} & \epsilon_{xy} & 0 \\ \epsilon_{xy} & \epsilon_{yy} & 0 \\ 0 & 0 & \...
photonica's user avatar
  • 101
0 votes
2 answers
47 views

Why is potential continuous at dielectric conjunction?

Lets take for an example, a spherical capacitor with two dielectrics. The Electric Field will then be given by $$\frac{Q}{4\pi\varepsilon_0\varepsilon_r r^{2}}$$ We know that then the electric field ...
MJSTX 's user avatar
0 votes
1 answer
30 views

Does an electric arc formed in air create more heat than in neon or argon?

When you create an arc in the air it becomes several thousand degrees and is hot enough to weld with. However, plasma arcs in neon/argon are cool to the touch, and are used for neon lighting and small ...
CaptainCodeman's user avatar
1 vote
1 answer
50 views

Effects of dielectric on force between charged bodies?

The electrostatic force between the plates of a charged isolated capacitor remains unchanged when dielectric fills whole space between plates. But when we take 2 isolated point charges in a dielectric ...
Garv Chaudha's user avatar
1 vote
2 answers
69 views

What are the conditions under which these equations hold for dielectric and magnetic materials?

$E_0 = \frac{D}{\varepsilon_0}$, $E' = -\frac{P}{\varepsilon_0}$ $B_0 = \mu_0 \cdot H$, $B' = \mu_0 \cdot M$ ($E_0$ refers to the electric field generated by free charges, or the external electric ...
smallerstar's user avatar
2 votes
0 answers
27 views

Definition of the displacement field in classical field Lagrangian

In a BSM related paper (in appendix B), the authors use an effective Lagrangian $\mathcal{L}_{EFT}$, and define the following fields: $$ \mathbf{D} = \frac{\partial\mathcal{L}_{EFT}}{\partial\mathbf{E}...
Doron Behar's user avatar
1 vote
1 answer
37 views

Volume Distribution of Bound Charge in an Isotropic Dielectric: when does $ \nabla \cdot \vec{E }=0$?

In Electricity and Magnetism by Bleaney & Bleaney (3rd Ed.) pg 18 they state: In a dielectric where $ \chi_e $ (the susceptibility) is uniform, isotropic and independent of field strength there ...
psychgiraffe's user avatar
0 votes
1 answer
123 views

Wave propagation in inhomogeneous media

There is a problem I'm trying to solve for some time now and is about the standard (?) approximation that it is made when one tries to solve the Helmholtz equation in inhomogeneous media, that is \...
user1524841's user avatar
1 vote
1 answer
114 views

Deriving the Clausius-Mossotti equation for linear dielectrics from Classical Electromagnetism

I've been presented the Clausius-Mossotti equation in my Electromagnetic Optics class, but I was not given any derivation of the expression: $$\vec{P}=N\alpha \left(\vec{E}+\frac{\vec{P}}{3\...
Lagrangiano's user avatar
  • 1,616
1 vote
1 answer
72 views

Field due to an infinite sheet of charge with dielectric on one side

Suppose you have a surface charge density $\sigma$ on a conducting plane $z=0$. The region $z<0$ is filled with a dielectric of permittivity $\varepsilon$. What is the field everywhere? I tried ...
ultralegend5385's user avatar
0 votes
0 answers
26 views

Derivation of the quantization of the EM field in a dielectrics

I'm currently studying the quantization of the EM field in a dielectric medium and trying to understand the quantization scheme of Huttner and Barnett (1992, see Phys. Rev. A 46, 4306). The system ...
Plax Manck's user avatar
0 votes
1 answer
36 views

How did the scientist measure the dielectric constant? Does the dielectric constant relate to an alignment with the electric field?

I heard that the dielectric constant of water is around 78. When we think about the way we get the $\kappa$ of water, Can we get the $\kappa_{water}$ by putting the water molecules on the $\vec{E}_{...
J.H's user avatar
  • 3
3 votes
2 answers
134 views

Why is $c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}$?

I'm sorry if this is a duplicate but I didn't find my answer. I'm currently studying maxwell's equations and I know that by comparing the wave equation for either the magnetic or the electric field \...
Axodarap's user avatar
1 vote
1 answer
44 views

Electric Field and Potential between two infinite sheets with multiple dielectric mediums [closed]

Suppose we have 2 infinite sheets, one lies on $z = 0$ with potential $V = V_0$ and another at $z = a + b$ with potential $V = 0$. There are two slabs of dielectric material with permittivity $\...
Star's user avatar
  • 11
0 votes
0 answers
31 views

Frequency dependency of dielectric constant

The graph of dielectric constant is not linear with respect to increasing frequency. Polarization mechanism cannot keep with the frequency, and hence the dielectric constant abruptly drops. I get ...
physics-unexpert's user avatar
0 votes
0 answers
15 views

Is it necessary that an Electric Field becomes $1/K$ times inside a dielectric in all cases?

Suppose in space, there is an electric field. Now we introduce a dielectric medium in space with dielectric constant $K$. Is it necessary that an Electric Field will become $1/K$ times inside a ...
Devansh Mittal's user avatar
0 votes
1 answer
45 views

Electric field due to bound charge on surface of dielectric material

I got stuck on a step in Example 4.8 of Griffiths. It places a charge $q$ a distance $d$ above an infinite linear dielectric material. The Problem It states the the field due to the bound charge $σ$ ...
Kids Free's user avatar
0 votes
0 answers
30 views

Force on dielectric while entering a capacitor - Connected to battery

I had seen a similar question to this as below. However it considers a charged capacitor disconnected from a voltage source. Force on dielectric slab As per my understanding from the comments, the ...
Sai's user avatar
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