Questions tagged [coulombs-law]
A fundamental and empirical law quantifying the electrostatic force between two charges.
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Computing the potential difference between two points using $\ \vec{E} \>=(xî + yĵ + zk̂)\frac{kQ}{(x^2 + y^2 + z^2)^{3/2}}$ [closed]
The potential difference between two points, A to B, is given to me as
$$ΔV= -\int\limits_A^B \vec{E} \cdot d\vec{r}\ . $$
Since this is my first time seeing something like this as a first-year ...
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Why electric potential can be evaluated by conservative electric field?
The definition of electric field is following:
The electric field is defined at each point in space as the force per unit charge that would be experienced by a vanishingly small positive test charge ...
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Attractive or repulsive force between two statically charges plates [duplicate]
So I'm trying to calculate some mechanics for an electrostatic attraction/repulsion system and I want to make sure that I'm using the correct numbers. I did a bunch of research on my own and I think I ...
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Calculating electric field produced by spherical shell [closed]
I'm having trouble solving this problem.
Find the electric field a distance $z$ from the center of a spherical surface of radius $R$ that carries a uniform charge density $\sigma$. In here, $R>z$. ...
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Potentials of two near conductors
When two conductors (let's say spherical) of charges $q_1$ and $q_2$ and radii $r_1,r_2$ respectively are brought and connected by a metal rod,we know that flow of charge occurs unless potentials are ...
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A question about Coulomb's law for one moving and one stationary charge
let one charge is moving and another charge is stationary (compulsory). Then the electric force between them can be calculated by coulomb's law?
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Definition of Coulomb's law
In the article about Coulomb's law
There is following sentence:
Coulomb's law is an experimental law of physics that calculates the amount of force between two electrically charged particles at rest.
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Limitation of Coulomb's law
The Coulomb's law is an expertimental law which calcuates the electrostatic force between distinct two electrically charged point particles (point charge) at rest.
And Point particle doesn't take up ...
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Why do gravity and electricity sometimes obey inverse square laws over the same distance scale?
Is this a chance mathematical coincidence or is there a good physical explanation for it?
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Validity of coulombs law for a charge in motion [duplicate]
If there is a charge $Q$ kept firmly at rest and another charge $q$ is brought in the vicinity of $q$,it's obvious that $q$ will accelerate towards $Q$. Now,when we say that coulombs law is not ...
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Electromagnetic influences in electric field
Let us imagine a charge $q$ in space. At each point in space,there is an electric field vector associated with it. Now we start moving the charge in a direction. We know that electromagnetic ...
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Dipole formation in electrostatic induction
Let's bring a positively charged rod near a conductor. Now since some electrons in outer shells are not strongly bound to atoms,they will get to the side near the rod. But why does it mean that dipole ...
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Charge distribution on an infinitesimally thin, elliptical conducting thread
Assume an elliptical conducting thread, which is positively charged. Although the thread is considered to be very thin, its stiffness is great enough in order not to allow the Coulomb's forces between ...
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Static condition of surface charges
We know that when charge is supplied to a conductor,they rearrange themselves on the surface thus making a static equilibrium condition. Let's suppose we have $+2e$ charge on a plane sheet conductor. ...
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Definition of proportionality constant in Coulomb's law
My textbook, which was written before 2019, says:
$k$ [Coulomb's constant] is defined in terms of $c$ to be precisely $k=(10^{-7}\ {\rm N\cdot s^2/C^2)}c^2$
$\implies\displaystyle\frac{1}{4\pi\...
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Why sodium ion is able to atract negative charges? [closed]
Why is the sodium ion able to attract negative charges? even though it has 1 excess proton, its electrosphere is further away than the nucleus, wouldn't it be possible to counterbalance the effect of ...
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Two-body problem + shield
Let us consider two point charges, one positive, one negative, interacting via Coulomb force.
In the absence of any other force, this system constitutes an elementary example of two-body problem, and ...
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Charged particles accelerating toward one another gain both kinetic and potential energy
If we have two particles (let's just say of equal but opposite charges, $-q$ and $q$) and place them a distance $r$ apart, the potential energy of the system is:
$$
U = k \frac{q^2}{r}
$$
Now if we ...
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Separation energy of nucleons and Coulomb barrier
My question is related to this topic: Tunneling of alpha particles. Unfortunately it didn't quite solve my doubts.
My professor and the book I'm reading (Particles and Nuclei: An Introduction to the ...
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Quantifying the quantum electric field for $E$-fields that are not waves
In every physicists training, an electrostatics course will show how to solve Maxwell's equations for different systems, solving for the $E$-field at different points in space.
A separate solution to ...
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Can a consistent theory of electric force exist where charges of equal sign attract each other and charges of opposite sign repel each other?
I am preparing tomorrows lesson about electrostatics and the Coulomb law and wondered the following:
By simple experiments we can show that the electric force can be attractive and repulsive, so we ...
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Does the charge distribution of two uniformly charged conducting spheres change as we bring them near each other?
Assume that we have positively charged two solid conducting spheres of the same radius and material. It is evident that the surface charge is uniform on them to eliminate the internal electric field ...
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Coulombian barrier fission
Protons and neutrons in a nucleus are both in a well of $\sim$ 50 MeV (obviously that depends on the specific nucleus), but the shape of the quantum well is different because there is the Coulomb ...
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Tetrahedral Geometry and Potential energy
Intuitively, I'd think it possible to use potential energy to find the bonding angles in methane, but I'm not getting the right answer. Am I missing something?
In a tetrahedral, the faces are ...
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Question on Coulomb force compared to Newton gravity
I have recently started reading Volume 1 of The Feynman Lectures on Physics. I am going through Chapter 2, Section 2-2 Physics before 1920.
I came across this particular discussion within section 2-2:
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I can't use $\int \frac{kdq}{\mathcal{r}}$ to calculate the electric potential of an infinite charge distribution, can I?
Since $\int \frac{ kdq }{\mathcal{r}}$ assumes infinity is the reference i can't use it to calculate the electric potential of an infinite charge distribution, right?
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Are there specific paths (tunnels) inside a superconductor for which any moving electron feels a zero net Coulomb's force?
I want to know what the zero electrical resistance of a superconductor means. Does it mean when we connect the terminals of a battery with a superconducting wire, the electrons move within specific ...
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Why are Coulomb forces on two charges the same?
I wanted to explain to a person knowing some very very basics of physics, why the force of attraction on two charges $Q_1=3nC$ and $Q_2=-1nC$ are the same. Of course my interlocutor thought that $3nC$ ...
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Coloumbs law notation and math [closed]
I am currently taking Electricity and Magnetism I for Graduate school and we are of course using Jackson Classical Electrodynamics 3e. I am used to Griffiths from undergrad and intro physics in that ...
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Why is Coulomb's law still relevant?
There is no scenario where we can use Coulomb's law. There is no static charge. Even if we consider the local charge density to be constant for a system of charges, the individual charges are still ...
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Coulomb field from QED
It is well-known how to obtain Coulomb's law in perturbative QED (e.g. the answers to this question on this site). I am trying to understand if there is any reasonable way to give a meaning, within ...
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Can we calculate electric field exactly at surface of charged sphere? [closed]
For a uniformly charged sphere, electric field at surface of a solid sphere is given as:-
$$E=\frac{KQ}{r²}$$ (if radius is r)
So did we actually calculate electric field at surface of sphere or just ...
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How to find force on point charge due to distributed charge system?
How to find force on charge +q by uniformly charged rod(or ring) of charge +Q. I know how to find electric field but I am confused whether we can use the formula:-
$$F=qE$$
Because the charged object ...
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Can we apply Coulomb's law for accelerating point charges when they are at rest?
Can we apply Coulomb's law for accelerating point charges at the instant when they are at rest?
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What is an electric charge? [duplicate]
If electric charge is a property of matter that puts a force on other materials. Then why each object doesn't get repelled Or attracted?
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Rutherford's experiment
I have read everywhere that the gold foil experiment performed by Rutherford was done hoping that the alpha particles face only a little deflection/no deflection however this doesn't sit right with me,...
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Two electrons, initially at rest, are separated by a distance $r$. What will be the distance between them after a time $t$? [closed]
I thought a lot about it but couldn't come to an answer. It's obvious that there must be an equation telling the answer. If one of the electrons were fixed, by Integral calculus, I would have found an ...
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How is gate-screened Coulomb potential derived?
In two-dimensional materials, the Fourier Transform of Coulomb potential $V(\vec{r})=\frac{1}{r}$ is
$$V(\vec{q})=\int V(\vec{r})exp(-i\vec{q}\cdot \vec{r})d^2r=\frac{2\pi}{q}\sim\frac{1}{q}$$
This ...
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Absence of Coulomb's force [closed]
I am interested in understanding the potential consequences if Coulomb's force were to suddenly vanish on the behavior and interactions of various objects. If this fundamental force suddenly ceases to ...
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Why is current density proportional to electric field strength, and why does this relation seem contradictory to Maxwell (and others)?
I've got three physics equations in mind which seem (to me) to contradict eachother, using a simple case of charge(s) in a static electric field. If someone can give an explanation as to what I'm ...
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How does a nucleus manage to gather the energy to withstand the constant force applied on it from the protons? [closed]
The force repulsing two protons never goes away, meaning that there is a constant force pushing the protons apart forever. Firstly, where are these protons getting the energy to constant apply this ...
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Infinite line charge - why dependent on $r$?
For an infinite line charge, the Electric field at a point depends on $r$. While I understand the proof of this by Gauss’s law, with intuition, not so much.
The explanation people go by is the more ...
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Inverse square law of a photon in QED
So in Feynman's QED book strange theory of light and matter, he mentioned as a photon travels, it spreads a little, thus the "arrow" shrinks inversely with distance, and that is the inverse ...
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Why do same-charge particles repel each other? Would anti-particles exhibit the contrary behaviour? [closed]
Coulomb's Law states that same-charge particles repel each other and opposite-charge particles attract each other.
Coulomb's Law formula is:
This is related to Maxwell's equations:
An example of an ...
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Quantum Analog to Kepler's First Law
According to Kepler's First Law, the orbit of a planet is an ellipse round the sun with the sun at one focus. There's an inherent asymmetry in this. Instead of the sun being in the dead center, its ...
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Unknown integral identity in derivation of first Maxwell equation
Reference: "Theoretische Physik" (2015) by Bartelsmann and others, page 391, equation (11.23).
While deriving the first Maxwell equation based on Coulomb's law, the authors are using the ...
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Why is the alpha particle beam in the Rutherford experiment not affected by the electrons?
The force exerted by the nucleus on the alpha particles is electrostatic in nature. So, why does mass has an effect? How do we conclude that the electrons don't effect the alpha particles from the ...
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Shouldn't Electric Potential energy be $U=2kQq/r$?
Let's take 2 charges $Q$ and $q$ a meter apart. Say you want them to collide. You'll have to apply force $F$ on charge $q$ (which I know is changing with distance). I know we integrate this force and ...
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Symmetry which shows that the magnitude of electric field due to infinitely large sheet doesn't depend on perpendicular distance from the sheet
The magnitude of electric field due to a uniformly charged, infinitely large sheet is
$$E = \frac{\sigma}{2\epsilon_0}$$
($\sigma$ is surface charge density)
It is a constant for all points in space, ...
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Can a huge amount of protons heavily packed cause electrical breakdown?
As far as I'm concerned, it's much more difficult for conductors to carry protons than electrons.
So, the internal charging limit equation (Q = E ε0 A) does not apply to proton charges? If not, how ...
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