The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [coulombs-law]

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

Filter by
Sorted by
Tagged with
1
vote
3answers
67 views

Newton's third law and Coulomb's law

Coulomb's law states that if we have two charges $q_{1}$ and $q_{2}$, then $q_{1}$ will act on $q_{2}$ with a force $$ \textbf{f}_{12}=\frac{q_{1}q_{2}}{r_{12}^2} { \hat {\textbf {r}}_{12}},$$ and $...
1
vote
2answers
24 views

Why are there 6 interactions with 4 positive charges?

From a homework assignment, there are 4 spheres spaced 1cm apart. Each of the spheres are charged to +10nC and weigh 1 gram. The question wants us to find the final speed of the charges once they've ...
1
vote
0answers
31 views

What is the function $q$ in the definition of charge density?

Supposed we define $\lambda = \frac{dq}{dl}$. If I think of this intuitively, this makes sense; the linear charge density at a point is tiny amount of charge at that point divided by the tiny length ...
-2
votes
1answer
31 views

How to calculate this electric field? [closed]

I can't solve this question. Please help. Q: Solve using Multiple integrals (Gauss is not allowed). A hemisphere of radius $R$ has a uniform distributed surface charge density $ρ_s$. Calculate ...
0
votes
1answer
21 views

What is the effect of charge of Sun induced on the Earth as compared to gravity?

As we know gravity is a less attractive force than the for of electric and magnetic fields. My question is where does the effect of magnetic field go while gravity has pull on earth. At this point ...
1
vote
1answer
40 views

What would be tension developed in a conducting ring of radius $R$ which has been given a charge $Q $, uniformly in the ring? [closed]

As the question says , i thought about using coulumbs law , but for any small dq charge , all other part will be attracting it , so.how to get the total tension force ( difficulty is in as distance ...
0
votes
0answers
15 views

Is this calculator for the electric field inside of a square correct?

I made a desmos tool calculating the components of the electric field [u,v], at a point (a,b) inside of a square of continuously and uniformly distributed charge with linear charge density $c$. https:...
0
votes
3answers
66 views

Do electrons in the same orbital but different spin feel each other's Coulomb repulsion?

Or is it irrelevant, as orbitals are QM while Coulomb interactions are classical physics? What I think I understood of orbitals is that particles with the same quantum numbers cannot occupy the same ...
0
votes
0answers
11 views

Electric field inside of a thin square of charge centered around an axis and extruded infinitely along that axis

Consider a thin square of charge centered around an axis and extruded infinitely along that axis in both directions. Is the electric field at any point inside of this shape zero, as it is for a ...
3
votes
2answers
130 views

How to find the electrostatic potential of a hydrogen-like charge density?

I've been trying to find the scalar potential that would correspond to the charge density of a ground state hydrogen atom. The result is known, and the inverse of my problem can be found e.g. in ...
-1
votes
1answer
106 views

If Coulomb's were to depend on $\frac{1}{r^n}$ instead of $\frac{1}{r^2}$ where $n\neq 2$,would Gauss's law still be the same?

What I think is that Gauss's law is an independent law of nature which shouldn't change on modifying Coulomb's law.Am I correct? Well the relation between Gauss's law and Coulomb's law is very strong ...
3
votes
1answer
50 views

Is the electrostatic equilibrium that conductors reach a consequence of Coulomb's law?

We know that if charges were to be placed within a conductor, they would start to rearrange themselves until they reach an electrostatic equilibrium where all charges are 'still' and no $E$-field is ...
1
vote
3answers
102 views

How are inverse square laws verified? [closed]

I'm curious about how equations like $F_{g}=G\frac{m_{1}m_{2}}{r^{2}}$ and $F_{e}=k\frac{q_{1}q_{2}}{r^{2}}$ were derived. Turns out that they're actually inverse square laws. But it's still unclear ...
-2
votes
1answer
51 views

Electric field of a finite line uniformly charged

A charge $Q$ is uniformly distributed along the $z$ axis. Why because of the symmetry of the configuration is the electric field zero at z=0? I understand the electric field cancellation in a ...
1
vote
1answer
36 views

Understanding distances and unit vectors in this problem

A charge $-q$ is at $x = -a$ and a second charge $+q$ is at $x = a$ Between the charges, the contribution from each charge is in the negative direction. An expression for $${\overrightarrow{E}} = \...
0
votes
2answers
57 views

Accurately calculating the work to move a charge? [closed]

I'm applying a force $F_{me}$ to move the charge $q_2$ towards $q_1$. If they are both equal charges, I'm assuming a repulsive force $F_R$ opposing me. In order to get $q_2$ to the final position ...
1
vote
1answer
53 views

Coulomb's law and the continuous charge model in an infinite charged plane [duplicate]

The $E$-field of an infinite plane with a uniform charge density $\sigma$ has a constant magnitude equaling $2\pi\sigma$. Now, this magnitude assumes a continuous charge model throughout the plane. ...
-1
votes
1answer
52 views

Work done by charged particles [closed]

A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particle is also a proton and in another, ...
0
votes
1answer
37 views

Why did the experimenter touch the circular plate in this demonstration?

In this introductory physics experiment demonstration, the experimenter went through the following procedure: First, he charged the rectangular plate by rubbing it with fur. Next, he laid a ...
0
votes
1answer
37 views

Why is the force due to a charged loop on a charge on its axis only in the axial direction?

This may be more of a mathematics question, but I am going through the open course for physics II, from Yale, and am learning about Coulomb's Law. One of the first examples the professor gives is ...
0
votes
0answers
26 views

Electrostatic force between 2 charges when the medium's dielectric constant is continuously changing

This question just came to my mind. I don't know if it's valid or not. I'm just curious. Question: Charge q1 and charge q2 is in a medium and it's dielectric constant changes proportional to the ...
0
votes
0answers
10 views

Electrostatic force between charges placed in 2 different mediums [duplicate]

Here is the problem. Question: What is the force between the 2 charges? So, If I convert medium 1 into medium 2 keeping the force constant then, (considering an imaginary charge q where the 2 ...
0
votes
1answer
43 views

Modifying the Hamiltonian when there is a presence of the Coulomb interaction

Referring to the Hamiltonian of a system of free electrons, $$ H_0= \sum_{\sigma} \int d^3rd^3r' \psi_{\sigma}^{\dagger}(\mathbf{r})\left(- \frac{\hbar^2}{2m}\nabla^2\right)\delta(\mathbf{r}-\mathbf{...
2
votes
1answer
37 views

Discontinuities in electric fields

I'm a mathematician self-studying physics for fun and I'm trying to wrap my head around a simple concept, which is a consequence of approximations. Basically, by Coulomb's law, if I have a point ...
17
votes
5answers
3k views

How can electric field be defined as force per charge, if the charge makes its own, singular electric field?

The electric field $\bf{E}$ represents how much force would act on a particle at a certain position per unit charge. However, if we actually place a particle in that position, the electric field will ...
2
votes
1answer
171 views

Difference between Coulomb law and QED

According to Coulomb law, the electromagnetic force between point charges separated at zero distance is infinite. Does QED explains the same result, or there is any difference?
0
votes
1answer
85 views

Is Coulomb's law correct? [duplicate]

Why don't electrons and protons collide? Hydrogen atoms are often ionized. After ionization, it is divided into electrons and protons, which can merge into hydrogen atoms at any time. Why don't ...
1
vote
3answers
70 views

Electric field generated by a small object

I've just begun to study electrostatics and I've read the coulomb law, it describes the electric field generated by a point charge as characterized by a spherical shape. I think it is due to the fact ...
-1
votes
3answers
52 views

Force between 2 plates of a capacitors , which approach is correct? [closed]

If I have a parallel plate capacitor with charge $Q$, to calculate the force on first plate we say the electric field of $\frac{Q}{2\epsilon_0 A}$ is created by the second plate and since the charge ...
11
votes
4answers
1k views

How is linear momentum conserved in circular motion?

Consider a system of two charged particles ($+\text{ve}$ and $-\text{ve}$). Let's assume that the negatively charged particle revolves around the positively charged particle due to the force of ...
1
vote
2answers
73 views

Problem in understanding superposition principle in electrostatics

When I have a single charge, it produces a electric field and a test charge will experience a force. Now when I have two(identical,same sign) charges, they produce electric fields and when the test ...
1
vote
0answers
38 views

Relativistic Particle Motion and Numerical Methods

I want to be able to show the relativistic motion of a particle in a static electric field produced by a proton at the origin: $$ \vec{E} = \frac{1}{4\pi\epsilon_0} \frac{q}{r^2}\hat{r} $$ The ...
1
vote
1answer
32 views

How can system of charges be static?

I am a beginner in electrostatics. I don't understand the below: When we have a set of charges, those charges exert a force on the test charge but what I don't understand is how are these set of ...
1
vote
0answers
24 views

For which energetic reasons are ions blocked by cell membranes?

The permeability of cell membranes is given by the following diagram from the book "Biochemistry": The reason that ions get blocked can be explained chemically: The ions favor interactions with the ...
1
vote
0answers
82 views

How to write the Rutherford differential cross section in terms of the momentum transfer?

The Rutherford differential cross section is: $$\frac{d\sigma}{d\Omega} = \frac{Z^2 \alpha^2}{4E^2 \sin^4 (\theta/2)}.$$ I need to write this in terms of the momentum transfer $\frac{d\sigma}{d(Q^...
12
votes
2answers
1k views

Why is it that forces like gravity and electricity (approximately) basically act between pairs of bodies only?

In classical mechanics, with the limit of little movement (so no relativity, waves, and/or "magnetic" effects), we can see that gravitation and electricity can both be described as "two-body" forces, ...
0
votes
1answer
24 views

Electric Potential: Building system of point charges

How can we prove that the amount of work we have to do to build a system of point charges is same , whether we place the point charges one by one or all at once
-1
votes
1answer
113 views

Electric force between two hemispheres of different radii? [closed]

Two hemispherical thin shells made of insulating materials are concentrically arranged in a free space as shown. The radii of the smaller and larger hemispheres are ‘R’ and ‘2R’ and they carry ...
0
votes
1answer
45 views

Is the direction of the Coulomb force at short distances indeterministic?

Suppose we have two electrons that apply a Coulomb force on each other. At large distances, we can consider the two electrons as point charges and the direction of the Coulomb force would be on the ...
2
votes
2answers
121 views

Electrostatic values where there are some charge

I've started asking myself: What is the value of the electric field at the surface of a shell with uniform distribution? In particular, is it infinite, as this point is over an (infinitesimal) ...
0
votes
2answers
50 views

When was Coulomb's constant made/established?

Charles-Augustin de Coulomb lived from 14 June 1736 – 23 August 1806. Coulomb's constant is $$k_{\text e}=\alpha\frac{\hbar c}{e^2},$$ a form of Planck's constant is included, but Max Planck lived ...
0
votes
0answers
51 views

Is this a valid explanation for why charges in a conductor move to the outer surface?

This is a drawing of a spherical conductor with a hollow center. The black dots represent +ive charges, and the arrows represent their electric fields. I am assuming the black dots start on the inner ...
4
votes
3answers
1k views

Can the electrostatic force be infinite in magnitude? [closed]

The magnitude of the electrostatic force between two charges $Q$ and $q$ separated by a distance $r$ is given by $$F=\frac{kqQ}{r^2}$$ but the minimum value of $r$ must be $10^{-15}\ \rm m$. Therefore,...
1
vote
4answers
109 views

How did Coulomb measure charges?

I was studying some Electrodynamics when suddenly this question popped into my mind : The whole of Electrodynamics is based on the Coulomb's Law. There is no derivation of this law because it is an ...
0
votes
1answer
41 views

Quantifying potential energy

As per the definition of potential energy we kept a fixed charge, and in the presence of an electric field of the fixed charge, we release another charge of the same sign moving towards the fixed ...
7
votes
5answers
806 views

Doubts in understanding some concepts of potential energy

Let us consider a system of charges in space. The potential energy of the system of charges is determined by the amount of work done by the external force to assimilate the charges in that manner. But ...
0
votes
1answer
53 views

Why isn't electric potential infinite?

In my textbook, I've read that electric potential is the work performed to carry one unit of positive charge to electric field from infinite distance. We know that, W = Fs So here the distance is ...
1
vote
1answer
68 views

Integrating Laplace's equation over a sphere

The Wikipedia page on Laplace's equation states that if the Laplacian of $u$ is integrated over any volume that encloses the source point, $$\iiint_V \nabla \cdot \nabla u \, d^3V =-1.$$ I can'...
0
votes
1answer
59 views

How do we know how much charge is in an object?

It's a little science history question but I really wonder how did peoples measured the amount of charge in an ball or something or like in coulombs case how did he measured the electrical force ...
1
vote
1answer
156 views

Coulomb's Law Question

The presentation of Coulomb's Law in various books occasionally has a note that the test charge, q2, must be small enough that it doesn"t alter the field of the first charge, q1. The same limitation ...