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 ...

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Stability and Laplace's equation

Consider four positive charges of magnitude $q$ at four corners of a square and another charge $Q$ placed at the origin. What can we say about the stability at this point? My attempt goes like this. ...
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where has the energy gone when the test charge turned away?

Consider an insulated ball with some charge $q_1$ inside it.Now we take a small area over that ball uninsulated i.e we had cut a small portion. Now when we bring a test charge from infinity near that ...
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Drawing the lines of force for an electric field varying in magnitude but having a constant direction

How will the electric lines of force look for an electric field varying in magnitude but having a constant direction, say along +ve z axis ? According to me, since the electric field is varying in ...
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102 views

The image current due to moving charges and a current carrying thin wire

Suppose we have a plane conductor and positive charged particles of mass m are moving parallel to the plane conductor at a distance d. The trajectory can be assumed to be straight. An image current ...
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Induced charge on a shell

If a charge +Q is placed off-center inside a neutral conducting shell,can we comment that the charges induced on the inner surface is such that the net force on the +Q charge is zero?If so,how?
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How can flux be the number of electric field lines normal to a surface? [duplicate]

Shouldn't the number of field lines through any surface be infinite if there is a charge present. Or is there a finite number of field lines from a unit charge?
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Electric potential is zero but non zero electric field?

What is the physical significance of such a point where electric field is non-zero but electric potential is zero? I mean, how can we understand this concept without mathematics?
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How is electric dipole moment analogous to mechanical moment?

Diplole moment is q*2l. I don't understand the similarity between dipole moment and ordinary mecanical moment.
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Why do electric field lines point in the direction of decreasing electric potential?

Why do electric field lines point in the direction of decreasing electric potential? I came across this sentence in my school book but am trying to understand this ever since. I know that dV=-E.dr ...
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153 views

How does electrostatic force affect electronic devices?

How does electrostatic force generated by two seperate plates having opposite charges affect electronic devices? I know that magnetic fields have some harmful effects to electronic devices but I am ...
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54 views

Is there a way to induce a net negative electric charge in an electrically conductive material, and If not why?

From what I've been reading, moving electrons don't compress relative to the protons within the atom, For reasons that I'm having difficulty understanding. Seeing that this is the case I would like to ...
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Do electrostatic fields really obey “action at a distance”?

In an electromagnetic theory class, my professor introduced the concept of "action at a distance in physics". He said that: If two charges are at some very large distance, and if any one of the ...
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56 views

Electric field in a non-uniformly charged sheet [closed]

So if we have a large sheet that is not uniformly charged and is NOT a conductor, how can I find an expression for the electric field everywhere? Things we know about the sheet: the width is 2b it ...
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52 views

Finding the electric field of a NON uniform slab? [duplicate]

If we have an infinite slab that is not uniformly charged and is not a conductor, how can we find an expression for the electric field everywhere? Here's a picture Things we know about the slab: ...
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79 views

Concrete example of the application of complex analysis in electrostatics [closed]

I've heard complex analysis can be useful in solving electrostatics problems, but despite doing some research I was unable to find any concrete examples. Would anyone be able to provide a simple ...
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31 views

Electric Flux through metal plate by uniformly charged wire

Suppose a long uniformly charged wire is placed parallel to a thin uniform metal plate of length l and width $w$. Distance is $r$. Then how to calculate the electric flux through the plate if the ...
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59 views

Electric Field At Centre Of Non Uniform Ring

In the above solved example why only the cos components have been taken for calculation of electric field at centre ? Why not the sine components ? BTW in case you say that the sine components ...
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17 views

How will open-circuit voltage affect the Fermi Level Difference

The circumstances of my question consists of this: I have two materials, copper and cesium, and they are sandwiched together with a layer of cesium in the middle. It is connected only on a single side ...
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125 views

Capacitance of spherical capacitor when earthed

The capacitance of a spherical capacitor is given by $$C=\frac{4\pi \varepsilon_{0}}{\left ( \frac{1}{a}-\frac{1}{b} \right )}$$ How can I find out the capacitance of the capacitor when The ...
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279 views

Force due to combination of free space and dielectric

I will make a generalized form of my question. There are two point charges $q$, $x$ distance apart. And there is a dielectric slab of thickness $t$ and of dielectric constant $K$. Should the force ...
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1answer
34 views

Work Function Calculation with Local Electrostatic Potential

On the Wikipedia site, it describes the work function equation as W = -e\phi - Ef, where phi is the electrostatic potential of a vacuum nearby the surface of the material. So my question is, how can I ...
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132 views

How does the conductor knows which side is outside?

For a electrostatic equilibrium state, we know charges only stay on the outer surface of the conductor. But, how does the conductor know which side is outside? If it's about the curvature, then ...
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42 views

Minima & maxima of Laplace's equation

I don't get the following sentence from David J. Griffiths' Introduction to Electrodynamics (the ambiguous sentence is in bold) Laplace's equation tolerates no local maxima or minima; extreme ...
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1answer
254 views

Simulate / plot electrostatic field

I have something like this: For given voltage (9 V red wire, 0 V blue wire) I want to simulate electrostatic field. I already know, for example that in the point (10.5;0) there are 10 V and etc. I ...
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If we charge a capacitor can we discharge it into a battery?

I have read that we can charge a capacitor using a battery, but can the vice versa happen? My project needs to show a battery being charged through a fully charged capacitor.
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Capacitance of a single charged plate?

Lets say we have a single plate that has a charge of +Q on it. A plate with charge -Q is infinite distance away. Will the plate with +Q have a capacitance associated with it? Why or why not? I was ...
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Zero current induced in a loop

Consider the following two cases, Case 1 – A coil moving through a constant magnetic field Case 2 – A conductor moving through a constant magnetic field Now, in Case 1 (a coil moving through a ...
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Electric Potential Energy

When work is done on a positive test charge by an external force to move it from one location to another, does the potential energy increases or decreases, and does the electric potential increases or ...
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25 views

variation of electrostatic potential on moving radially outwards from the nucleus of an atom

I was wondering how would the electrostatic potential change on moving radially outwards from the nucleus in an atom, considering the effect of the electron clouds around it.
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258 views

How to find the electric field of a charged tube?

Let's say there is a charged tube(cylinder with no top or bottom) with radius $a$, length $l$ and charge $q$ and a point which is collinear with the centre of the charged tube. Anyway, since we can ...
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Comparison of capacitances

The figure shows two arbitarily shaped surfaces S1 and S2.S1 is a thin metal foil, which has been slowly beaten to form the surface S2 without any loss of charge.. S2 lies completely within or on ...
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Difference between parallel and series capacitors

Basically, I can't figure out that whether a capacitor is connected in series or parallel. The same problem occurs while solving for resistors. Can someone help me understand this difference ...
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48 views

When is work done on or by something?

An example, here what my textbook says: When charges are released In electric fields charges experience the force causing them to accelerate along electric field vectors. Positive charges ...
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19 views

Nucleus validation [duplicate]

Inside the nucleus of an atom is the Coulomb's law valid? I mean that between proton, neutron and other elementary particles, i.e., meson etc. What will be the limit or validity of charges between ...
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1answer
27 views

Electric Fields in a Neutral Object

A neutral object has no net charge since its positive and negative charges cancel each other. However, I’m wondering how, in terms of fields, they do cancel each other. Since fields are vectors, won’t ...
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725 views

Why electric field inside charged conductor is zero in the electrostatic case?

I am trying to understand the idea (or the fact) that most books introduce which is about the electric field inside a charged solid conductor Books tell that the field has to be zero everywhere ...
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Electric field between capacitors [closed]

A parallel-plate capacitor consists of two parallel, conducting plates of area $A$, separated by a distance $d$. Each carries a charge of magnitude $Q$; positive on one, negative on the other. ...
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Why the magnitude, $E$, of the field vector is different for every sets of (parallel) plates?

This is quoted my textbook. I wonder why we can't reproduce the same magnitude on a different set of plates, if we make them the same size, same charge, and having the same electric potential, and ...
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Is this diagram in my textbook not constructed to scale?

Or am I having an illusion. Clearly, the distance from 6v to 4v is not the same as 4v to 2v. I know it should be based on: $V = k\frac{q}{r}$.
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What is the strength of the magnetic field required to penetrate an average human body?

Introduction Suppose you are an experimental nanobot researcher trial-ling a new form of medication that involves activation and control of nanobots within the cells of the interior of the human body ...
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1answer
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Is the sea of electrons in a metal at rest when the metal is in electrostatic equilibrium?

It is said that charges inside a metal in electrostatic equilibrium are at rest, and are stationary. However, don’t the electrons have their own thermal vibrations and whatnot? Aren’t they always ...
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41 views

Earnshaw's theorm and Effective potential

Earnshaw's theorm says "no stable equilibrium for any $\frac{1}{r}$ potential field in charge-free space". Now I am confused in some aspects, and I would like some helping hands. 1.)General physics ...
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247 views

Is Gauss' law valid for time-dependent electric fields?

The Maxwell's equation $\boldsymbol{\nabla}\cdot \textbf{E}(\textbf{r})=\frac{\rho(\textbf{r})}{\epsilon_0}$ is derived from the Gauss law in electrostatics (which is in turn derived from Coulomb's ...
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56 views

Why isn't the electric field zero in the empty space?

A spherical portion has been removed from solid sphere having a charge distributed uniformly in its volume the electric field inside the emptied space is? Isn't the electric field suppose to be zero ...
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41 views

Potentials of electrical multipoles vs strong interaction

Are there any reasons of the similarity? As I remember both potentials have the form $$\sim e^{-\alpha r}/r$$ where $r$ is the distance. The comment of Bort below led me to Wikipedia ...
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Why does power loss in pure metal caused by temperature is calculated base on $P=I^2R$ but not $\frac{U^2}{R}$

$$P=I^2R=\frac{U^2}{R}$$ The metal's resistivity is temperature dependent, neglect the change in size by temperature. The power loss of a pure metal when it drop form temperature $T_1$ to $T_2$ is ...
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Why does the area of the plates affect the capacitance?

Why does the area of the plates affect the capacitance? Lets say I have a parallel plate capacitor with a charge of 10C and a potential difference of 5V. By the definition $C=Q/V$, the capacitance is ...
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235 views

How do electrons distribute themselves along a wire attached to one pole of a battery?

Let's assume we have an electrochemical cell, like an AA battery. We attach a long straight wire to the negative terminus of the battery, the other end of the wire extends right away from the battery ...
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Electric Potential Between Two Like Charges

At the point horizontally across and equidistant from the centers of the two charges (also oriented horizontally), what is the electric potential? At that point, the electric field of the first charge ...
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Do permanent magnets have an electric current surrounding them?

Permanent magnets seems to have different properties to electromagnets, such that electromagnets can be used for induction and energy transfer if a conductor is placed within their changing magnetic ...