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### Calculating pressure on a dielectric kept inside a capacitor

Firstly, the pressure is because of the opposing forces acting on both sides of the dielectric slab. On the left side of slab, the field due to the left plate is $\frac{\sigma}{2\epsilon_0}$ and that ...
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### Dielectric field in a homogenous electric field

I'm working through my workbook right now and currently am stuck on the chapter about dielectrics. The term $\vec{E}=\frac{3}{\epsilon_r +2}\vec{E_0}$ was introduced without a proper proof. Instead ...
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### Are insulators non-ohmic conductors?

Can insulators/ dielectrics be considered as non-ohmic conductors ? As they apparently breakdown when sufficiently large potential differences are applied across them.
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### what can be the BG and dielectric constant of monolayer MoS2 in semiconducting state (2H) and in metallic state (1T)

Monolayer MoS2 is a semiconductor that can undergo an MIT (Metal to insulator) or semiconducting state to insulating state transition. The semiconducting state is referred as 2H State and the metallic ...
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### What's the meaning of linear medium in electromagnetism?

I'm studying the book Polarimetric Radar Imaging: From Basics To Applications and on page 31, there's this sentence: In the following, we shall consider the propagation of an electromagnetic ...
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### Nonlocal dielectric function - what does it mean?

I'm reading this* article and in the second sentence of introduction I encountered a term I haven't heard of before. Namely: nonlocal dielectric function. What does this nonlocality mean? And how does ...
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### Why there are spikes in permittivity Vs. frequency curve?

When the frequency is increased the permittivity of a dielectric material decreases. But in the way of decrease there are some spikes which indicates sudden increase of permittivity for certain ...
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### Qualitative understanding of excess heat capacity in ferroics

I'm looking to understand what an excess heat capacity in a ferroelectric (FE) can correspond to qualitatively. Typically one starts with a Landau expansion of the free energy if you want to study the ...
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### Surface bound charge in the electric displacement

In Griffiths, the electric displacement is written with just volume charge density, and that is because, he says, 'we cannot apply gauss law precisely at the surface of a dielectric, for here volume ...
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### How does a bulb light up when it's connected in a circuit with an uncharged capacitor and a cell?

Since there is a capacitor, isn't it an incomplete circuit? How does the current flow across the dielectric medium? If a bulb was connected to a cell alone and if there was a break in the wires of the ...
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### The truest/most general Maxwell's equations in isotropic, linear, inhomogeneous media with sources

Sources use $\mu H=B$ and $\epsilon E= D$, assuming homogeneous media. Obviously if $\mu$ is space varying, $\nabla . (\mu H)$ need not be equal to $\nabla . B$ What is the most general form for ...
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### Calculating rise in water surface due to a charged capacitor

﻿Two metal plates separated by a distance d & initially charged with charge +Q & -Q are kept so that it just touches the surface of a very large water tank as shown in figure a. Thus water ...
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### Does polarization take place in non polarized solid?

According to polar - non polar division polar substances like H2O have dipole moment but unpolarised matter like O2 doesn't have dipole moment I.e. Dipole moment = 0. But my question is does ...
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### Calculate characteristic frequency from atomic polarizability

With Lorentz model, the plasma frequency can be calculated from electron density $$\omega_p=\sqrt\frac{4\pi N e^2}{3m}$$ But I also found in this paper that it could also be calculated from atomic ...
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### Density of polarisation charge is zero always for linear isotropic homogeneous dielectrics?

It seems to me that the volumetric density of polarisation charge in a linear homogeneous isotropic dielectric in an external field is always zero, but I find this rather surprising. Consider such ...
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### What is the origin of the “polarization catastophe”?

According to the Clausius-Mossotti relation, $$\frac{\epsilon_r - 1}{\epsilon_r + 2}=\frac{n\alpha}{3\epsilon_0}$$ So when $n\alpha = 3\epsilon_0$, the relative permittivity $\epsilon_r$ ...
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### What would be electric potential due to induced charge sphere?

We know that the potential at the center of the charged sphere (if it is conductor) would be $$V_o = \frac{1}{4\pi E_0}\frac{+q}{x}$$ If the distance between charges is x from their center of the ...
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### In the electric field we have dielectrics.What about the magnetic field?

Do we have insulators in the magnetic field just like we have dielectrics in the electric field? How are they called and how do they work?
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I read the description and the explanation of the result of the experiment in my book but still I can't understand it. Here is the process of the experiment. A pair of concentric metallic spheres ...
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### Why does the medium affect the Coulomb's constant but not the gravitational constant?

Why does the medium affect the Coulomb's constant but not the gravitational constant? My friend said maybe the particles of the medium affect the electric field. But the net charge in the medium is 0 ...
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### What is the meaning of permittivity of free space?

We all know about the value of permittivity of free space but is this actually enough of for our knowledge? We should be taught that what actually does permittivity of free space means.
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### Force between charges when there's a slab of dielectric between them [duplicate]

Consider the following arrangement - Blue and red are two opposite charges +q and -q separated by a distance R. A dielecric slab is placed between them. The thickness of the slab is t. What will ...
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### Dielectric constant of Transition Metal Dichalcogenides (TMD)

Why is the in-plane dielectric constant of transition metal dichalcogenides larger than the out-of-plane dielectric constant? Is this because of the spacing between monolayers of the TMD? Why do these ...
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### Dielectric slab inserted into a constant voltage capacitor

I was told that a dielectric slab inserted into a capacitor connected to a battery (constant voltage) will be repelled, because the energy stored in the capacitor increases when the dielectric is ...
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### How to find dielectric constants of ferroelectric materials experimentally?

What is the procedure to find out dielectric constant of barium titanate at different temperatures ?
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### Dielectric heating - does EM field transfer energy to polar molecules?

In AC field, polar molecule are trying to align with external field. At high freguencies, changes of field are so quict, that molecules cannot align with it. This leads to increasing kinetic energy of ...
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### Why breakdown voltage decreases with increasing FWHM of an asperity?

I am running a simulation for a dielectric breakdown. I am getting breakdown voltage decreases with FWHM, which does not make sense as field enhancement is higher for a small width. Simulations solve ...
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### The advantages of a dielectric in a capacitor

In a capacitor a dielectric can be placed in between the two plates. I have trouble understanding the points / advantages of a dielectric from what I have read in a text book. The points written there ...
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The dielectric slab surrounded by air as shown in diagram has permittivity $\epsilon$ different from air and permeability almost same as air. Electric field everywhere within the slab is given to be $$... 1answer 131 views ### Charged dieletric/conductor in capacitor It is a standard problem to consider a dielectric or a conductor between the parallel plates of a capacitor. But what happens to capacity, voltage, charge, inserting between the plates of an ideal ... 0answers 1k views ### How are band gap energy, dielectric constant (permittivity) and resistance related to each other? The following three properties are related to current flow: Band gap energy Dielectric constant Resistance I would expect them all to have the same trend (i.e. higher band gap energy would cause ... 3answers 1k views ### Why is signal bad in a tunnel? Consider this: you are driving through a tunnel listening to your AM radio and a GPS, all of the sudden AM radio has nothing but statics and your GPS says "reconnecting - please hold". You say to ... 1answer 733 views ### Force per unit length between two long parallel wires, one of which is insulated Suppose we have two very long parallel wires of radius a and distance between their axes d (d>>a). The first wire if is carrying charge of linear charge density \alpha and is insulated ... 0answers 75 views ### Validity of the static limit of a dielectric function In general, the dielectric function \epsilon(q,\omega) reflects the spatial and temporal response of a condensed matter system to an applied potential. If we put an electron into an electron sea, ... 1answer 64 views ### Question about wavelength of EM wave in dielectric Many websites (http://maxwells-equations.com/materials/permittivity.php) lists out the following formula as to how you can compute the wavelength of an EM wave in a dielectric$$\lambda_d = \lambda_o/...
We know that the capacitance of a capacitor depends on the dielectric material in between the plates as $$C=\dfrac{K\epsilon_0 A}{d}\,.$$ But what if the electrode material is changed? For example ...