All Questions
Tagged with capacitance gauss-law
90 questions
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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 ...
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22
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Potential difference between two non-grounded equipotential plate
I am attempting to solve for the potential difference between two non-grounded equipotential plates using Poisson's PDE. The relevant Maxwell equation considered is $∇⋅E=\rho$, where $E$ represents ...
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Understanding Gauss' Law on Charged Sheets and Oppositely Charged Plates
I'm grappling with understanding Gauss' Law as applied to charged sheets and oppositely charged plates.
From what I've gathered, when using a Gaussian pillbox encompassing both sides of an infinite ...
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83
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Electric fields around plates of charge vs sheets of charge, and then made into a capacitor
I've read over several other discussions on the topic of "electric field of a sheet of charge vs electric field of a charged plate", on this very site, but I still haven't gotten the answer ...
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Do conductor plates encloising charged particles exert a force on one another due to the charges induced on them? How to calculate in a 1D model
I would very much appreciate some guidance on the below.
Consider a one-dimensional world as depicted in the attached figure.
We have two (lets say positively charged) particles enclosed by two ...
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How to know which formula to use for the electric field of a conducting plate of charge? $𝐸=σ/2ε_0$ or $𝐸=σ/ε_0$? [duplicate]
I'm so confused right now as I have come across questions regarding the E.F of a conducting plate of charge.However some questions use 𝐸=σ/2ε0 whereas others use 𝐸=σ/ε0 and I genuinely don't know ...
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Electric field between two thin infinite charge sheets with opposite surface charge density [duplicate]
Consider two infinite parallel plans of opposite charge density Let's say $+\sigma$ for the left plane and $-\sigma$ for the right plane. Why is the electric field calculated this way?
$$
E=\frac{\...
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Parallel plates uniformness
All questions are highly related, so I preferred to ask them together.
Q1: Why is the electric field uniform between parallel plates and is it only uniform between? and not outside?
Q2: Why uniform? ...
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142
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Can we use superposition of electric fields to conclude that between plates of capacitor the field is $2\frac{\sigma}{\epsilon_0}$? [duplicate]
Consider a parallel plate capacitor. This is a setup of two very large parallel plates, each a conductor and each with area $A$, and one having positive charge $Q$ and the other negative charge $-Q$.
...
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Parallel plate capacitors when one plate is a mesh
The capacitance per unit area of a parallel-plate capacitor is $\frac{\epsilon_0}{d}$.
But what if one of the plates is a mesh, but the distance $d$ is much much greater than the size of the holes in ...
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Having a problem understanding the density charge per unit area in a coaxial cable (capacitor)
Given the following scenario, why is the charge per unit area not the same with opposite sign? I am finding it difficult to understand, since the charge per unit area for two parallel plates in a ...
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210
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Cylindrical capacitor and charge density per unit area [closed]
I am dealing with the following problem:
Assume that a charge has been placed on the inner cylinder, and that the entire charge is distributed on the outer surface of the inner cylinder as shown in ...
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Why do two infinite planes contribute to Electric Field but not two surfaces in co-axial cylinder
I understand why the electric field between two infinite planes is $\frac{\sigma}{\epsilon_0}{\vec{e_z}}$. Both planes contribute to the field - the upper positive charged plane "pushes" ...
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Is the commonly derived Gauss' law for a parallel plate (insulator/conductor) often derived wrong? [duplicate]
I am very confused about plates (conductors/insulators) and applying Gauss law. It seems like gauss law for the isolator is very often derived wrongly.
In short: if you have an infinite plate (...
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260
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Increasing capacitance of a capacitor [duplicate]
In my book, it's given that:
”Principle of Capacitor: In the capacitor arrangement, the increase in capacitance of a conductor is due to the decrease in potential V (charge Q remains constant) when ...
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Why is the electric potential for a point charge is $V=kQ/r$ but for the capacitance of parallel plate , the electric potential is $V=E*D$? [duplicate]
From what I've learned since now, I always knew electric potential is inversely proportional to radius or distance for a point charge, but I've come across the electric potential in a parallel plate ...
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545
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The difference between $V=kQ/r$ and $V=ED$ ($V$ is electric potential)? [duplicate]
I realize $V=kQ/r$ is the electric potential of a point charge while the other one is the electric potential in a uniform electric field, but in the first case the distance (radius) is inversely ...
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343
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Electric field due to a large, non-conducting plate and factors of 2 [closed]
I'm trying to derive the electric field due to a single large, thin, non-conducting plate at a point (see figure). I'm solving it using 2 methods, and arriving at a different answer using both.
I've ...
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A strange electric field, can it exist? [duplicate]
If the electric field strength is $E_x=x, E_y=E_z=0$, then by $\nabla\cdot E=\frac1{\epsilon_0}\rho_e$ where $\rho_e$ is the density of charge, we get $\rho_e=-1$ for any point in the space.
But if $\...
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Electric field between two parallel plates
In my class we derived an expression for an electric field due to an infinitely long plane of charge and it given as:
$$\bf{E} = \frac{\sigma}{\epsilon_0}\hat{\bf{r}}$$ where $\sigma$ it is the ...
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When do we use the formula $E=kQ/r^2$?
A cube of side 20 cm has its center at the origin and its one side is along the x-axis, so that one end is at x = +10cm and the other is at x = -10cm. The magnitude of electric field is 100 N/C and ...
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Potential and capacity of parallel plate capacitor [closed]
Given is a capacitor consisting of 2 sheets stretching out infinitely at $z = \frac{d}{2}$ and $z = -\frac{d}{2}$ which has a surface charge density $\sigma = \frac{Q}{\Delta F}$.
It's potential is ...
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412
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How to apply Gauss's law when dielectric constant in a capacitor varies continuously?
Let's say the problem is to compute the capacitance of a cylindrical capacitor with a dielectric material between the plates. The capacitor is considered to be long enough to ignore end effects. The ...
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The volume enclosing the charge in Gauss's law: does it have to be simply connected?
I was trying to apply Gauss's law to a simple problem: Find the capacitance of a cylindrical capacitor. Inner radius is $a$ and outer radius is $c$. The space between the plates is a dielectric ...
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317
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Electric field between two conducting plates both with zero potential and volume charge density between them
The questions says that two very large, conducting, parallel plates separated a distance
$2a$ contain a uniform volume charge density $ρ$ between them and they both have zero potential, the ...
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Electric Field stays the Same even though Distance Increases?
I was working on physics homework and came across this multiple choice question.
Two metal plates of area A and separated by a distance d are placed in parallel near each other to form a capacitor ...
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Time-domain model of a capacitor when the capacitance is varying with time
The current through a capacitor as a function of time is given by;
$$i(t)=C\cdot \frac{d}{dt}U(t)$$
When assuming that the capacitance $C$ does not vary with time.
But what if it does?
I don't know ...
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Charge density inside dielectric with conductivity
Consider the figures I and II
, they consist of similar circuits with identical batteries. There are two different slabs connected in the circuit, both are geometrically identical and have the same ...
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Does the capacitance of a capacitor depend on the type of dielectric that is NOT between the capacitor?
In the image above there are two infinite planes. The infinite plane at $z = a$ has a surface charge $\sigma$ while the infinite plane at $z = 0$ has a surface charge $-\sigma$. The dielectric that ...
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Failing to understand use of one-dimensional upper limit in area variable
I am trying to learn capacitance of a parallel plate capacitor, while learning i noticed the portion where they are calculating potential using line integral. Now, there is a term "ds" which is the ...
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Difference between the plate of a capacitor and an infinite plane of charges
I would like to understand what is the difference between the plate of a capacitor and an infinite plane sheet of a Charge? I mean, when we use Gauss' law to find the electric field between to plate ...
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Gauss law when dealing with materials with conductivy
Suppose we have a parallel plate capacitor filled with two dielectrics materials, one with conductivity $\sigma_1$ and permittivity $\epsilon_1$ and the other one with conductivity $\sigma_2$ and ...
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Why is the electric field of a conducting sheet of charge double the electric field of just a sheet of charge?
I was reading Feynman's Lecture on the Application of Gauss' Law and I came across this:
Source
This really confused me. What are the "other" charges he talks about? How does the additional field ...
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Why don't capacitors hold charges on the outer walls of the plates? [closed]
Suppose I have two metal plates in a vacuum and I give this system some electric charge,the charge would distribute itself according to Gauss law on both the inner and outer walls of both plates...but ...
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Doubt in the derivation of Gauss's law in dielectrics
so in the 2nd page,when the dielectric material is introduced the gauss's law becomes $$\oint _ { S } \vec { E } \cdot \vec { d S } = \frac { ( q - q _ { i } ) } { \epsilon _ { 0 } }$$.But my ...
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Electric field between capacitor plates
When we try to find the electric field between the capacitor plates, what is the right way to do it? This is one of the ways I've seen and I don't understand why:
Using a Gaussian cylinder on the ...
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Gauss's Law on Parallel Conducting Plates
I have a question regarding the application of Gauss's law to find the E-fields produced by two parallel conducting plates. My textbook (Halliday and Resnick 9e) states that there is no E-field above ...
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How does charge movement vary between insulators and conductors?
I've been reading A Student's Guide to Maxwell's Equations by Daniel Fleisch, and he states:
in nonconducting materials (called "insulators" or "dielectrics"), charge does not move freely, but may ...
user231751
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Electric field in capacitor arrangement with different dielectric media
Please consider the following arrangement of infinitely extended charged plates. In z-direction the system also extends to infinity. The charged plate in the middle of the figure is 2x negatively ...
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Induced surface charge for a conductor within two parallel plates that carry different charges ($+Q$ and $-2Q$)?
This is my first question and appreciate all your help.
An infinitely wide conductor is parallel to two infinitely wide planes with surface charge density $-2𝜎$ and $+𝜎$ respectively.
How to find ...
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Why are the two outer charge densities on a system of parallel charged plates identical?
One of the ways examiners torture students is by asking them to calculate charge distributions and potentials for systems of charged parallel plates like this:
the ellipsis is meant to indicate any ...
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Question on capacitance
I am recently trying to learn electrics on my own but am a bit confused with regard to capacitance. By Gauss law, I understand that the electric field from a single parallel plate results in:
$$ E = \...
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Why do we not have devices like inductors or capacitors to hold gravitational field? [closed]
I know that a capacitor can store electric field and an inductor can store magnetic field. So is there a way that gravitational field field can be stored in any such device. Also we do not have a law ...
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4
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Why is the electric field between two parallel plates uniform? [duplicate]
According to sources online (eg HyperPhysics) the electric field strength around a point charge is $$E=k\frac{Q}{r^2}$$
This must means that the further you get away, the electric field should ...
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7k
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Electric Field between two parallel plans of opposite charge density
So considering two infinite parallel plans of opposite charge density let's say +σ for the left plan and -σ for the right plan
Why is the electric field calculated this way :
$$
E = σ/2εo + σ/2εo ...
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Proving electric field constant between two charged infinite parallel plates
It is known that the electric field intensity between two infinitely long charged parallel plates is constant.
I had read that one explanation is that if a test charge is placed between the plates, ...
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Flux is not coming zero, although charge inside it is zero!
In the figure, there are two capacitors connected in series. So, they have same charge on them. Since, the plates have same area, therefore they have same charge densities σ.
Also, one capacitor have ...
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Confusion regarding Gauss law and capacitors
In book (Halliday Resnick Krane, 2nd Part, fifth edition), it's written that when you you put some charge in an isolated conductor, then within around $10^{-9}$ seconds the charges all go to the ...
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Capacitors electic field
If we have the electric field on the surface of a conductor being $E=\sigma / \epsilon_0$ where $\sigma$ is the charge per unit area then why is the combined $E$ field from two parallel plates not 2x ...
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Why is electric field constant at any point due to infinite plane of charge while a finite plane of charge can give the same result ?
We know that the electric field is constant at any point irrespective of the radius due to a plane sheet of charge of infinite extent and can be proved by Gauss theorem however I don't understand why ...
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