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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1answer
122 views

Physical interpretation of single layer potential in the plane

Let $\Omega\subset\mathbb{R}^2$ be a bounded domain with smooth boundary $\partial\Omega$. The single layer potential with charge density $f$ sitting on $\partial\Omega$ is defined by $u(z)=\...
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3answers
307 views

A charge $Q$ is placed at a distance $a/2$ above the center of a horizontal square surface of edge $a$ [closed]

A charge $Q$ is placed at $a$ distance $a/2$ above the center of a horizontal square surface of edge $a$, while a second charge $Q$ is placed below one of the vertices of square. Find the flux of ...
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0answers
83 views

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 ...
2
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1answer
50 views

Is it possible for two polarizable bodies to induce dipoles in each other in the absence of an external electric field?

If there exist two initially neutral bodies (say atoms) some distance apart, with no external electric field applied, can they induce dipoles within each other?
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2answers
67 views

How can we prove that electric field originate from and terminate on charge using Gauss Law?

We already know that electric field originate and terminate on charge only and they doesn't make any closed path. But is it possible to prove this statement using Gauss Law ? If yes then how ?
2
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3answers
125 views

Parallel-plate capacitor working voltage $V={Qd\over{\epsilon_0 A}}$ relationship with plates' distance

I don't understand why the working voltage of a capacitor increases with the plates' distance. Suppose we have 2 capacitors in series where $C_1=12,0\mu F$ and $C_2=4,0\mu F$. The voltage over both ...
0
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1answer
112 views

What is the distribution of charge on two conducting spheres?

There are two conducting spheres of charges $Q_1$ and $Q_2$ and respective radii of $r_1$ and $r_2$ with center-to-center separation of $L$. Can the distribution of charge on each of the conducting ...
0
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2answers
71 views

Proof that work is the same whaever the path of approach for two charges

I have a quick question on a figure that outlines a proof. There is a stationary charge $q_1$ and is kept fixed. $q_2$ is moved to the same position along two different paths at a fixed distance ...
1
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1answer
42 views

single conducting plane and parallel conducting plane with opposite charge all have different Electric field but same Electric Flux?

Considering the electric field $\vec{E}$ created by an infinite conducting plane $M_1$ having surface charge density $\rho_s$ locate at xy plane at $z = 0$ with $\hat{a}_z$ as unit vector $$\vec{E}=\...
2
votes
3answers
85 views

Does the equation CV = q break down when V is small or a wire is very long?

I'm trying to understand how the equation $CV=q$ relating the voltage difference and charge stored on a charged capacitor breaks down under extreme circumstances. In most problem statements that I'm ...
1
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1answer
201 views

Real life physics problem: Why is my desktop computer affected by my plasma ball?

Note: this is strictly a physics question, not meant to be an advertisement I was running my desktop with a plasma ball on the side. The desktop has a touch screen enabled. I started to notice that ...
2
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3answers
6k views

Why the electric potential of earth is zero?

For a localized charge distribution the potential is set to zero far away from the charge distribution (at infinity) Now, when grounding a conductor, i.e. connecting it to Earth, it is said that we ...
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1answer
64 views

electric field in hollow conductor

when we have a hollow conductor and we charge it then the quantity of charges and electric on and in inner surface of conductor material is zero and this is okay .But is the electric field also zero ...
0
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1answer
46 views

Confused about voltage due to a point charge

If we have a point charge q then on any point around q we have electric field done by q on this point, and there exist voltage(potenial) of this point due to q which is work done by q to move +1c from ...
0
votes
1answer
57 views

Electric field and Gauss law

If we take a Gauss surface S to calculate the electric field using Gauss law:$\int\epsilon\vec{E}.\vec{dS}=\sum(Q's\ inside\ S\ +$ $Q's\ on\ S\over2 $ $)$ then this field calculated $E$ is for what?...
0
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1answer
88 views

Potential and Electric field

I'm trying to find the electric field from the potential and vise-versa but I'm having trouble I know the electric field of a ring with radius a and charge Q to be $$E=\frac{Qx}{4\pi \varepsilon_{0}(...
-1
votes
1answer
117 views

Equipotential inside a conductor ring, but how do I determine the value?

I was mapping the potential lines of 2 cylindrical electrodes - one at 0 V, the other at 5 V. I have a metallic ring midway between the 2 electrodes. I know that the electric field inside the ring is ...
0
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1answer
40 views

why isn't the net force considered while calculating potential due to a system of charges?

The textbook I'm reading defines potential at a point as work done per unit charge by an external agent to move the test charge from the reference point to the point under consideration (without ...
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2answers
103 views

Using Gauss's law (differential form) on an infinite line of charge

I just read about Gauss's law in differential form and how to compute divergence. I worked out the $1/r^2$ field and got zero as expected! I was very happy. Then I thought the infinite line of charge, ...
0
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0answers
510 views

How do i prevent static electricity on my trampoline? [duplicate]

Every time i am on my trampoline, i get a nasty static shock when i get down. I have no idea how this is caused. How do i prevent this? My trampoline is a 8ft trampoline with a net surrounding it.
1
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1answer
71 views

Is the electron's magnetic dipole moment influenced by the measurement method?

The electric charge of an electron at rest is a constant value and is not influenced by the measurement instrument. The measurement instrument by itself can give more or less accurate result, but does ...
2
votes
2answers
985 views

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 ...
0
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2answers
87 views

a question about work needed to move a charge towards another one [duplicate]

Consider two charges $q_1>0$ & $q_2>0$ separated by a distance $d_1$, and we want to move charge $q_2$ to a distance $d_2$ from $d_1$ where $d_1-d_2>0$. I need to calculate the work ...
1
vote
1answer
213 views

Why does the field of an electric dipole drop off as $1/r^3$?

Electric field of a point charge drops off inverse squarely but that of a dipole varies as $1/r^3$. Why the field drops off more quickly for a dipole?
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2answers
86 views

simple force question

So given this diagram, I was supposed to find the magnitude and direction of the net force on the -10nC charge on the bottom right corner. I found the magnitude by myself using Coulomb's law for the ...
0
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3answers
235 views

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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1answer
118 views

What is the meaning when we say something is at the higher potential and the other is at lower and wht is the direction of flow of charge? [duplicate]

Electric potential is defined as the work done in bringing per unit positive charge from infinity to a point in the electric field of some other charge. let me explain what i actually want to ask. ...
1
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1answer
192 views

Point with zero electric potential inside triangle [closed]

If we have three equal point charges placed on a two dimensional plane at $(a_x, a_y)$, $(b_x, b_y)$ and $(c_x, c_y)$, what would then be the coordinates of the point at which the electric potential ...
1
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1answer
99 views

Static electricity and insulators

I've read that Stephen Gray in his experiments on electricity, he has found that static electricity can be conducted -transferred- through an insulator thread made of silk. So, how could that happen ...
0
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1answer
39 views

Electric Flux through a lamina

I was wondering what the electric flux would be through a square (or any planar lamina for that matter) if I placed a charge at the centre of the square. I think that it will be 0 since none of the ...
2
votes
2answers
210 views

Potential of an infinitely long cylinder

Suppose I have an infinitely long cylinder with radius $R$, charged with longitudinal density $\lambda$. I want to calculate the potential outside the cylinder. The field induced by the cylinder is $...
1
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1answer
45 views

What do we mean by this statement : “some positive charge is put on a metal piece”?

What do we mean by this statement : "some positive charge is put on a metal piece" ? (I know it will be distributed on the surface of the metal piece, if metal is isolated.) Electrons are ...
7
votes
5answers
16k views

How can I prevent my son building up static on his trampoline? [duplicate]

Whenever my three year old son plays on his trampoline, it doesn't take very long for him to start building up a significant amount of static electricity. His hair stands on end (which is quite ...
2
votes
1answer
74 views

Calculating the potential of 2 spherical perfect conductors with the image method

I am searching for a way to calculate the potential on the surface of two perfect conductors that are spheres. I am not sure my method is correct. Here is a diagram of what I am studying : They ...
2
votes
5answers
985 views

If the electrostatic potential is zero, why doesn't the electric field have to be zero?

I thought the relation between the electrostatic field $\vec E$ and the electrostatic potential $V$ is as follows: $$\vec E = - \nabla V$$ Thus, when $V$ is zero, $\vec E$ is also zero.
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1answer
506 views

What happens when a conducting plate is grounded?

(1) When I ground a conducting metal plate, is all the charge on the plate transferred to earth? By this I mean charge on surface of the plate and charge inside the plate. Inside metal plate there ...
0
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2answers
71 views

Why does the sphere with the smaller radius (r1) have the greater charge density?

Suppose two charged conducting spheres of different radii $r_1$ and $r_2 > r_1$ are very far apart but connected by a conducting wire. Why does the sphere with the smaller radius $(r_1)$ have the ...
2
votes
1answer
84 views

Sign of Gaussian surface that encloses negative charge

I can't solve a contradiction that have appeared in my head. Let's assume we have a negative charge, if we enclose it by a spherical surface and $A$ is surface of the sphere, then we will have $$\...
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0answers
60 views

Calculating the amount of charges for an object that is electrostatically induced

Induction is one of the ways to get an object electrostatically charged. While positive charges accumulate on one side, negative charges accumulate on the other side for an object in an electric field....
1
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1answer
167 views

Physical intuition for quadrupole source

In his Theory of Vortex Sound M. S. Howe defines sources "mathematically" (i.e. dipole is a source that could be described as a vector and than there is proved that it's equivalent to a two point ...
2
votes
1answer
890 views

Electrostatic force has longer range than strong nuclear force?

In my revision guide it says that the electrostatic repulsion between protons in a nucleus has a longer (indefinite, actually) range than the strong nuclear force keeping the nucleons together. So I ...
0
votes
1answer
181 views

What is space charge and how to calculate it?

I want to clarify the meaning of space charge. What I know is that the space charge is the total charge in a small region in space. I really confuse this in the ion beam context. Many text book says ...
0
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1answer
56 views

Question about particles in electric fields. Homework question

I am currently working on a homework question and I realized that I don't really understand some of the material that we covered so I hoped that you guys can help me clear up some misunderstandings. ...
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1answer
205 views

Why is the strong nuclear force > electrostatic repulsion?

In a nucleus there is a gravitational force between the nucleons and also electrostatic repulsion between the protons, and since electrostatic repulson >> gravitational attraction, it follows that ...
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1answer
53 views

Does Earth also move due to some electrostatic forces?

Does the earth experience some electrostatic forces due to other planets...which also make it move? My question is..whether the earth also moves due to electrostatic force of attraction or only due ...
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1answer
267 views

Charging a capacitor (terminals)

When a battery is connected to a conductor electrons are repelled from the end of the conductor connected to the negative terminal of the battery and flow to the end of the conductor connected to the ...
4
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2answers
181 views

Need help on electric potential definition

I'm having trouble understanding electric potential. In my book it says "an electric force acts on a charge situated in an electric field." I understand this part. Then it goes on to say "If a charge ...
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1answer
36 views

Understanding the differences and applications of some electrical equations

In preparing for the AP Physics 2 test tomorrow, (the first year this test is being offered, so this material is not easily searchable), I've been doing some reviewing of the equation sheet and trying ...
3
votes
1answer
1k views

Why does Hauksbee's electrostatic machine produce light?

I'm reading on the history of the discovery of electricity and the electron, and I've went from reading about Rutherford's gold leaf experiment all the way back to Francis Hauksbee's spinning glass ...
0
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1answer
469 views

The definition of mutual capacitance

I am not sure I completely understand the definition of mutual capacitance. Let's say we have two conductors, $A$ and $B$, so that the following holds: Both conductors are isolated. $A$ is isolated ...