# Tagged Questions

Electrostatics is concerned with the electrical fields and scalar potentials of stationary electrical charges and charge distributions. Use this for questions about electromagnetic situations in which currents and magnetic fields are absent, otherwise use [tag:electromagnetism] and/or [tag:magnetic-...

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### Gauss Law - Infinite line charge

I came across a sentence which made no sense to me as I was studying the electric field of an infinite line charge: The flux through the FLAT ENDS of our cylindrical Gaussian surface is zero ...
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### Movement of electrons in conductors and insulators

In conductors, the electrons can easily move unlike in insulators that prevent them from moving. What properties in conductors and insulators make them act in such way? Is it related to the position ...
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### Definition of a line charge with Dirac delta function [closed]

Is the following statement correct for a line charge distribution $λ(x)$? $$ρ(\mathbf r)=λ(x)δ(y)δ(z)$$ If yes - what does it say?
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### Can a piece of metal have all of its conduction electrons stripped?

Can a piece of metal have all of its conduction electrons stripped? If so, has this been done and for what value?
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### What are the potentials of a battery with respect to earth?

Assume an open-circuit voltaic cell. We know that the cell maintains a potential difference between its terminals. That is $V_+ - V_- = E$. Now, if I connect $(-)$ to earth using the earth terminal ...
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### Gauss Law Question. Could anyone explain to me why does S3 is 0 in this lecture note example?

Why does S3 equal to 0 ? for E3 dot dA = 0? Could I also know why does dA1 and dA2 point up and down? while dA3 point to the right?
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### Maximum limit of charging a capacitor

We say that we can charge a capacitor in proportion to the potential difference we apply across its plates and the maximum potential difference depends on the dielectric strength of the medium. Now ...
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### Can I create a static electricity water magnet?

I came to watch a video that water dipole get attracted by static electricity. I wanted to know if I could make a static electricity device that could pull out all the water from a wet cloth.
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### Determining the Potential of a Loop with a Given Line Charge?

I am trying to determine the potential at a point $P$ for a loop consisting of two quarter circles, one with a given radius of $a$, and the other with a given radius of $2a$. There is a line charge on ...
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### Does a Description with Photons as Force Carriers Apply for Non-Radiative Systems?

What is the full quantum mechanical description of the statement from classical electromagnetism "the electric field of a uniformly charged infinite flat plane is constant"? By "full" I mean that I'm ...
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### HOW is electric field inside a conductor placed in an external field zero?

Lets assume that there is an external field +E acting on a conducting plate from left to right. Due to this, some electrons will drift from right to left to cancel out this electric field inside the ...
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### Balloon and Static Electrcity

I am learning about charge, but there is one thing I don't understand. In the above picture, I understand that the balloon sticks to the wall because of the attraction between the negative charge ...
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### What does electrically charged mean?

So I was reading my physics textbook and it said that "Suppose we have two metal spheres, one highly charged and the other electrically neutral." What does it mean by highly charged? Does that mean ...
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### Why a capacitor's potential increase until it is equal to the potential of the battery?

I understand that the potential between the plates of the capacitor increases as the circuit runs, but why it stops increasing exactly when it becomes equal to the potential of the battery?
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### Potential at the center of a cubical box

Problem 3.16 from "Introduction to Electrodynamics" by D. J. Griffiths. Five sides of a cube are at zero potential. One remaining side (insulated from others) is at potential $V_0$. What is the ...
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### Method of image charge for cylindrical conductor

I am simply puzzled that only for spherical and planar conducting surfaces the method of images is applied. Is it (really) impossible to find image charge or charge distribution which can simulate the ...
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### The electric field inside the shell [closed]

If we place a $+q$ charge in the center of a spherical shell, what is the electric field inside the shell?
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### Why is the total potential difference in a circuit the sum of the individual potential differences?

I am having difficulty in applying my understanding of electrical potential to circuits. Why is the total potential difference in a circuit the sum of the individual potential differences among ...
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### How can an electroscope measure voltage?

An Electroscope consists of a lightweight, conducting needle hinged to a conducting pole. If the pole is charged, the needle will deflect from its zero-point because it is charged the same way as the ...
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### Difference between $E$ field configuration, sheet of charge: infinite sheet of charge, conducting vs. non-conducting

This is a very easy question, but I often confused myself. Perhaps someone could explain this concept again: A non-conducting infinite sheet of charge has the electric field configuration \begin{...
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### How is the differential form of Gauss Law used?

How is the differential form of Gauss's Law $\mathbf{\nabla}\cdot{\bf E} = \dfrac{ρ}{ɛ}$ used? What I mean is, where am I measuring $E$ and what is $ρ$ in this context?
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### Does charged saltwater repel itself?

if you take a volume of saltwater, and charge it to a high voltage, will the water molecules repel each other and climb the walls of the container slightly, or does the fact that water is polar ...
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### Potential on a uniform

My doubt is in the part where he sets $V=V_s - \int{E dr}$. My idea is that he is summing two potentials, from the surface, and the one he's trying to calculate with the integral. Is that right? If so:...
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### What is the difference between an electric field and gravitational field? [duplicate]

Since the electrostatic field and the Newtonian gravitational field share a similar form: proportional to $$\frac{1}{r^2}$$ Is there any qualitative difference between motions under the ...
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### charge flow between a sphere (inside) a spherical shell irrespective of the charge of the shell

a small sphere of radius r1 and charge q1 is enclosed by a spherical shell of radius r2 and charge q2.If q1 is +ve charge .Then , charges will flow from sphere to shell ,when the two r connected by ...
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### The torque $\bf p \times \bf E$ on a dipole causes it to oscillate about $\bf E .$

The torque $p \times E$ on a dipole causes it to oscillate about $\bf E.$ Only if there is dissipative mechanism, $y$? Why does it not work without it?
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### Does magnetic induction produce potential across zero resistance wire?

If magnetic field is increased at a constant rate inside a zero resistance wire loop, then, according to Faraday's law , $$\varepsilon = \frac{dΦ}{dt}$$ Thus, a potential difference is produced. ...
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### Flux of electric field through a closed surface with no charge inside? [duplicate]

I'm reading the Feynman lectures on electromagnetism and in Vol II, Chapter 1.4 Vol. II, Chapter 1-4 he talks about the flux of the electric field and says that flux of $E$ through and closed surface ...
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### Why can't a compact 10 MeV electrostatic particle accelerator not be built?

I've been thinking about this problem for a while, since I want to see if a compact accelerator driven nuclear reactor can be built for powering aircraft and rockets. The reaction I am considering for ...
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### What would the $\nabla^2 V$ be at the border of a conductor?

We are studying laplace's and Poisson's equation for electrostatics in my class. It was cursorily said that $\nabla^2 V = \sigma / \epsilon_o$ at the surface of the conductor. This makes no sense as ...
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### Gauss' law in differential form for a point charge

I'm trying to understand how the integral form is derived from the differential form of Gauss' law. I have several issues: 1) The law states that $\nabla\cdot E=\frac{1}{\epsilon 0}\rho$, but when ...
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### Effect of introducing an external charge beside a Gaussian surface

As far as I know, Gaussian surface's are surfaces that enclose a net charge and are shaped in such a way that the electric field vector's magnitude is the same over the entirety of the surface. My ...