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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2
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2answers
390 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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1answer
35 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 ...
0
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1answer
52 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 ...
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1answer
33 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
30 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
63 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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2answers
840 views

Gauss Theorem:Electric field of an uniformly charged non-conducting spherical shell

I want to know the electric field of an uniformly charged non-conducting spherical shell. I know that in case of conductors(metals),the sphere can be shell or it can be solid,but in both the cases ...
0
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0answers
30 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
vote
1answer
39 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
91 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
49 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 ...
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1answer
65 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
53 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
80 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?
1
vote
1answer
32 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
vote
1answer
50 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 ...
1
vote
1answer
28 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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3answers
68 views

Is it possible that the charged sphere can lose mass by adding electron?

While studying Electrostatics, I was wondering about whether a charged sphere gains or loses mass while just adding electrons? If it is possible then the negatively charged sphere will have more mass ...
0
votes
1answer
30 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
30 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
33 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 ...
1
vote
0answers
32 views

Half infinite conductor and two charges [closed]

We have a half infinite conductor that fills half the space in the area left of the xz-plane (so $y>0$). We put two charges in the space right of it, one charge $+q$ at $y=d$ and one $+q$ at ...
7
votes
5answers
10k 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
58 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 ...
1
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5answers
60 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
41 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
33 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
40 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 ...
1
vote
0answers
16 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 ...
1
vote
0answers
42 views

is speed of light is the limit [closed]

If an electron is away from a proton about 1 kilometer and the proton is fixed what will be the velocity of electron when they collide? I calculated it its speed was coming out to be more than the ...
1
vote
1answer
106 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 ...
1
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0answers
36 views

Current in discharging capacitor through fixed resistor?

In the textbook I'm using for physics it says that the charge left on the plates of a capacitor after time $t$, that is discharging through a fixed resistor, is $Q=Q_0e^{-t/\tau}$ where $\tau=RC$ is ...
2
votes
1answer
50 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
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1answer
53 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
votes
1answer
45 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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votes
1answer
66 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 ...
8
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7answers
10k views

Why can two (or more) electric field lines never cross?

The the title is self explanatory, I guess. Why can two (or more) electric field lines never cross?
2
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0answers
32 views

Uniformly charged sheet and metal rods

A friend of mine asked me a question. Suppose there are two metal rods which are placed in front of a uniformly charged non-conducting plane one after other with their length perpendicular to the ...
1
vote
1answer
46 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 ...
0
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0answers
22 views

Dipoles and Potential Energy

I was pondering about electrostatics, particularly dipoles. How would one go about calculating the difference in potential energy of a dipole an arbitrary distance away from an arrangement of another ...
3
votes
3answers
136 views

Electric field in a conductor

Is it always true that the electric field in a conductor is zero? What would happen if I put a very big charge inside an ungrounded hollow conducting sphere like this image? The charges inside the ...
1
vote
1answer
43 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
votes
2answers
65 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 ...
1
vote
1answer
65 views

electrostatics and magnetism

Let a square loop be placed in a uniform electric field in a position of stable equilibrium. Then, because of the electric field, if the electric field is in the rightward direction then a positive ...
1
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1answer
26 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
886 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
votes
1answer
73 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 ...
0
votes
2answers
820 views

Why doesn't a gaussian surface pass through discrete charges?

I have read that Gaussian surface cannot pass through discrete charges. Why is it so? I have even seen in application of Gauss' Law when we imagine a Gaussian Surface passing through a charge ...
1
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1answer
140 views

Graph of electric potential

In my AP physics guide the graph for electric potential (for a radial field, i.e. point charge) and gravitational potential (for radial field, i.e. point mass) slightly differ from each other and I ...
0
votes
2answers
1k views

The energy of electric interaction between these dipoles? [closed]

I'm a physics tutor. This is not a homework problem. I'm unable to solve this problem. The energy of electric interaction between these dipoles will be: Choose the correct answer from: I tried ...