A fundamental and empirical law quantifying the electrostatic force between two charges.

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1answer
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Can we use motor comb with metal sphere of Van de Graaff generator without belt? [on hold]

Can we use motor comb with metal sphere of Van de Graaff generator without belt?
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30 views

What is Coulumb force at zero separation in classical picture [on hold]

Assume a classical world. What would be force between 2 point charges if their separation tends to zero? Assume charges are static. My professor claimed it would be finite. I request you to ...
1
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1answer
36 views

Why don't the nucleus break apart? [duplicate]

The nucleus of an atom is made up of protons and neutrons. So if there are many protons inside nucleus even though there are neutrons why don't this protons may repel away breaking nucleus apart? The ...
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2answers
56 views

What's the difference between $E=\frac{F}{q}$ and $E=\frac{kQ}{r^2} $? [closed]

Can $E=\frac{kQ}{r^2}$ only be applied to situations outside of parallel plates?
3
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1answer
51 views

How do non-contact forces work?

One question has been bugging me ever since I started learning physics, the textbooks successfully describe the empirical observations but haven't given any reasoning behind it. What I want to ...
4
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4answers
203 views

Electric field dependence on distance

How can it be proved that for a point charge, $E$ is proportional to $$1/r^2$$ using the concept of Electric field lines (or lines of force)? I tried to show that if field lines are close, then ...
-1
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1answer
56 views

Thus, what mediates the electric interaction between two electrons? [duplicate]

We are all learning since kindergarten that the electric interaction is mediated by photons. then you learn this photons are not real, there are real photons, true, but these do not mediate the ...
2
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1answer
126 views

What is the significance of the Inverse-square law? [duplicate]

Considering its occurrences in various fields like Electrostatics, Gravitation, Acoustics etc. how does the law bind these topics together?
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0answers
40 views

Time of free fall in a repulsive force [duplicate]

The formula for time of a free falling body when acceleration is not constant can be found in any answers here at this site and also at wikipedia. But I haven't been able to find any formula for a ...
8
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4answers
1k views

Why does an electron shell further away from nucleus has higher energy level?

Using electrical potential energy $V=\frac{1}{4\pi \varepsilon_0} \frac{Q_1 Q_2}{r}$ , a particle further away from nucleus has lower magnitude of energy. Using Coulomb's law, a particle further away ...
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0answers
20 views

Which is the form of Born-Mayer repulsion term?

I have found in many textbooks different and unclear form of the Born-Mayer repulsion term. I write the interatomic potential as $V(r)= -\frac{e^2}{r}+V_{BM}$ and for $V_{BM}$ I expected something ...
0
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1answer
44 views

Notation of a vector containing equation in a paper

I'm trying to implement Coulomb long range interactions into a molecular simulation program using a particle-particle/particle-mesh Ewald solver. The following equation from the paper "How to mesh up ...
0
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1answer
55 views

When two like charges are placed at a large distance from each other, do they attract each other? [closed]

So my friend and I were arguing about this. He insists that if two like charges are placed at a large distance from each other, they attract each other. I find this nonsense. This clearly violates ...
1
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3answers
125 views

How does the Electric Field create a force? [closed]

If we have 2 charged particles which are a certain distance away from each other, they either attract of repel due to the electric field created by both of them. But I don't understand the mechanism ...
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0answers
60 views

Is it almost impossible to separate two point charges stuck together?

$$F=k\frac{qQ}{r^2},$$ if $r\rightarrow 0$ then $F\rightarrow \infty$.
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0answers
57 views

Speed of the Coulomb Field Measured To Be “Infinite”

The paper "Measuring Propagation Speed of Coulomb Fields" by R. de Sangro et al points out that: ...the Lienard-Weichert retarded potential leads to the same formula as the one obtained assuming ...
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1answer
46 views

While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why?

While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why is it so? I'm referring to the book 'Physics by ...
1
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0answers
48 views

Coulomb's law and its application [closed]

I just read that Coulomb*s Law describes (a) the forces that bind atoms together to form molecules (b) the forces that bind molecules together to form solids. My question is Do a proton share ...
3
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4answers
557 views

Attractive force between capacitor plates

A textbook question requires me to calculate the force of attraction between plates of a parallel-plate capacitor. The answer provided is $\frac{1}{2}QE$. I am not entirely sure how they arrived at ...
0
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0answers
69 views

Why is there no negative mass? [duplicate]

We know that the entire matter has a property called mass. Charge is also a property of matter. If negative charge can exist, why don't negative mass exist? Also, like charges repel each other. Then ...
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3answers
88 views

What is the maximum reach distance of electric field? [duplicate]

if i charge small object by removing electrons and put that object in the middle of huge vacuum chamber (million of light years in size) does the electric field lines of that charged object still be ...
4
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7answers
273 views

Is the electric field of a volume charge distribution well defined?

Consider a volume charge distribution $\rho({\bf r'})$. The electric field at ${\bf r}$ is $${\bf E}({\bf r})=\iiint\frac{1}{4\pi\epsilon_0}\frac{\rho({\bf r'})}{R^2}\hat{\bf R}\, \mathrm d^3{\bf r'}$...
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1answer
46 views

Coulomb's law and electric field intensity [closed]

here is question and solution I can't understand why R_x= 4a_z please explain it detail! ;-(
0
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1answer
69 views

Are Coulomb's Law and Lorentz force always true for all phenomenon in physics?

I saw two equation about charge: Coulomb's law $$\mathbf F=k \frac{q_1q_2}{ r_{12}^{2} }\, \mathbf{\hat r} $$ and magnetic Force $$ \mathbf F=q \, \mathbf v\times \mathbf B$$ My question is:...
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2answers
50 views

Electrostatics Of Conductors

My textbook says that no excess charge can reside inside the conductor because electric field inside a conductor is 0. But say i introduce a positive charge inside a conductor, it generates its own ...
1
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1answer
65 views

Electric flux of a charged rod through a uniform disc

I have an assignment regarding electric flux. The question I was given has the following sketch: The first question was about the force on the rod from the disc at the $z$-axis. I reached the ...
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0answers
48 views

Exchange of virtual photons [duplicate]

How does the exchange of virtual photons as per QED explain the electrostatic attraction of particles of opposite charge?
0
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1answer
40 views

Applicability of coulombs law for objects in different dielectric media

Is the Coulombs law applicable for inter-medium interaction? Consider the example image shown below How can one deduce the angles the bobs might make if they are in different dielectric medium?...
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1answer
68 views

Which was the first Coulomb's constant value? [closed]

Which was the first Coulomb's constant value? I didn't found any info in the Internet. I need the first value of K to compare it with my experiment. Could you please help me?
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3answers
69 views

What does the $k_e$ in Coulomb's law and $G$ in Newton's Universal Gravitation Law mean?

I very well understand the proportionality relation that was used to derive these laws like $F$ is proportional to product of masses and inversely to radius squared and hence its proportional to the ...
1
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1answer
54 views

Is there an underlying reason why some forces are inversely proportional to the square of the distance? [duplicate]

This is the first time I'm studying those subjects (I'm still in high school) and my teacher couldn't give me an answer. I'm referring specially to Newton's law of gravitation and Coulomb's law of ...
4
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1answer
169 views

Problem from Purcell and Morin's Electricity and Magnetism: Holding the charge in place

This is the problem given in Purcell and Morin's electricity and magnetism book. (Problem 3.2 If you have the book) Figure: I was able to figure out that the charges on A,B,C,D cant be held ...
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0answers
36 views

Why is there a potential well near a hydrogen nucleus?

A hydrogen nucleus consists of a proton and the electric potential is given by the formula KQ/r where Q is +1.6×10^-19. So plotting a function of electric potential with distance r should give a ...
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5answers
93 views

Solving for $r=0$ in an inverse square law

This occurred to me in thinking about Coulomb's Law for a spherical insulator, but obviously can be asked of any inverse square law force calculation. For example, all things on the surface of he ...
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2answers
140 views

How much is a Coulomb, really?

I've heard it said in my physics class that a Coulomb "is a lot of charge". And I believe it; most of the problems I've done in the class so far involve charges on the order of micro-Coulombs (or, ...
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2answers
735 views

Graph for Coulomb force vs $1/r^2$

We know that when there is a relation like x inversely proportional to y^2, the graph would be like this: But in this question"Plot a graph showing variation of Coulomb force(F) versus $1/r^2$, ...
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1answer
63 views

Positions where the electric field is not defined

Can anybody help me to understand this statement given in my book? The electric field due to a discrete charge configuration is not defined at the locations of the discrete charges. For ...
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1answer
94 views

Four equally charged electrons are placed at the corners of a square. What charge should be placed in the center to keep them in place? [closed]

Here is a drawing: http://imgur.com/VdW1Xmv Trying to solve this question. I understand that the charge in the center needs to be positive, and the sum of all forces should be 0. But how do I ...
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3answers
82 views

$F\cos\theta$ is not proportional to $d\cos\theta$?

If I’m working in two dimensions and I wanted to calculate the net electrostatic force on charge C, where charges A and B are stationary, of the same charge, and placed on the y-axis equidistant ...
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0answers
50 views

Coulombs Law on Quarks [closed]

As from opinion from others the question don't seem to be clear so I did some changes. What is 5.33... it is 5+0.3+0.03+0.003+.... this sequence does not ends. now if we have a ball and we need to ...
4
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3answers
100 views

Do we know why the field produced by charge extends to infinity?

Do we have any model to show why charge field or magnetic field extends till infinity. Edit: I agree that according to coulombs law $1/r^2$ cannot be 0 but do we know why this happens.I think I am ...
8
votes
1answer
291 views

Why doesn't an electron's charge rip the electron apart? [duplicate]

Like charges repel. What keeps an electron's charge from repelling itself? This problem would come up if an electron was divisible and its parts had fractional charge. A related question is, ...
3
votes
3answers
123 views

What does the Dirac delta function physically do while deriving Gauss Law form Coulomb's law?

While doing this derivation, the the source coordinates are mentioned as "$s$" and the coordinate of the point at which field is to be calculated is mentioned as "$r$". Kindly follow this Wikipedia ...
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1answer
63 views

Source charge at the origin of a 13 polygon surrounded by 13 equal charge at each corners

Suppose there are 13 equal charges at each corners of an $n=13$ regular polygon. The test charge $Q$ lies at the origin of the $n=13$ regular polygon. In the case of an $n=12$ regular polygon, the ...
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0answers
44 views

Gravitons, photons and conservation of momentum

How can gravitons be emitted from a mass to cause an attractive force to another mass? The same question could be asked of attractive e-m forces as well. Don't these violate the conservation of ...
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2answers
60 views

How is the equation for force by charge or by mass discovered?

It's a newbie question. How is the formula for force between two charges or gravitational force between two particles derived. Is it just intuition or is there any method used to derive these ...
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1answer
79 views

Regarding the proof of Gauss's law

I know that this question has already been asked multiple times but I´m still not getting on the mathematical details behind the answers... So I hope that this question doesn´t get closed. First I ...
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14 views

Measure a current from a charged surface caused by charge separation

I have separated a charge in an electric field like here (http://elektroniktutor.oszkim.de/grundlagen/gr_pict/coulomb5.gif) and I put the metal out of the field. The charge density on the surface of ...
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0answers
61 views

What are the reasons for accepting Coulomb's law? [duplicate]

I read the Coulomb's first memoir on Electricity and Magnetism (Louis L. Bucciarelli english translated version), and found it to contain only three trials (as complained by many) to reach the ...
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3answers
80 views

How much energy does an electron have when it is situated right next to a negative point charge?

The formula for potential energy regarding point charges is $E=kQq/r$. If $r=0$, then will the energy be approaching infinity? But what about an electron in a parallel-plates situation where it is ...