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

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Deriving Coulomb's law from quantum electrodynamics [duplicate]

Is it possible to derive the Coulomb's law using the principles of quantum electrodynamics? How?
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where does the term half in the formula of electrostatic potential energy comes from?(system of point charges)

Electrostatic potential energy stored in a system of point charges (from wikipedia) The electrostatic potential energy $U_E$ stored in a system of N charges q1, q2, ..., qN at positions r1, r2, ...
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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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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 ...
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What is the intuitive meaning behind Coulomb's constant $k_e$?

What is the intuitive meaning behind Coulomb's constant $k_e$? If the force of an electric field can be calculated by $$F=k_eqQ/d^2$$ If I could guess I would say $k_e$ is the acceleration but I am ...
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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 ...
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30 views

dipole field on axis twice the field on perpendicular bisector

Why is the dipole field on axis twice the field on perpendicular bisector? For the perpendicular bisector: Lets assume -q is right from of the origin and +q is left from the origin, both a distance a ...
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62 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 ...
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Is there a fundamental relationship between Coulomb's law and Newton's Law of Gravitation? [duplicate]

It seems like the two equations are identical indicates that there is something more going on that unites them both, maybe in a cool way or something. Why are these two laws so similar?
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62 views

Why do inverse square forces not rise asymptotically for $r\to 0$?

An example of an inverse square force is the gravitational force: $$ F = \dfrac{G m_1 m_2}{r^2}$$ For large bodies I can understand why the force does not rise asymptotically as you get closer. For ...
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58 views

Induction in Electrostatics

While solving some problems on electrostatics, I came across this question : Two balls carrying charges of +3 $\mu C$ and -3$\mu C$ attract each other with a force $F$. If a charge of +3$\mu C$ is ...
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44 views

Lower limit value of electric force [closed]

What is the lower limit value to the electric force between two charges separated by a fixed distance?
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Infinite force between two point charges as $r$ approaches 0 [duplicate]

According to coulombs law the Force experienced by two point charges increases with the inverse square of their separation. This would imply that at distances approaching 0, the Force approaches ...
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67 views

Force when distance between charge is zero

According to coulomb law $$ F = \frac{q_1q_2}{r^2} $$ I want to know what happens to force when $r=0$. If $F \to \infty$ then the charges can't be separated! But if an unlike charge of higher ...
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49 views

Special relativity, electromagnetic fields, charge and Q

Is it true, were Coulomb's constant k to be several orders of magnitude smaller, that there would be no (or increasingly negligible) magnetic fields generated by moving charges? The reason being the ...
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50 views

Direction of electric field lines and electrostatic force

Direction of electric field and electrostatic force should be same by the equation $$\vec{F} = \frac{k q q_0}{r^2}$$ Electric Field $$\vec{E} = \frac{k q}{r^2}$$ Let us suppose that there is a ...
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31 views

Why does the medium affect the Coulomb's constant but not the gravitational constant?

Why does the medium affect the Coulomb's constant but not the gravitational constant? My friend said maybe the particles of the medium affect the electric field. But the net charge in the medium is 0 ...
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Electron Beam Welding equation

I am studying for a nuclear physics course right now and came across a question and topic that sparked my interest - Electron Beam Welding. As I understand it, the process heats up the metal by ...
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Will the electrostatic force between two charges change if we place a metal plate between them?

If a thin metal plate is placed between two charges $+q$ and $+q$, will this cause a change in the electrostatic force acting on one charge due to another? What is the concept behind this? What will ...
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72 views

Does the electric force on a charged particle in a uniform electric field increase?

If I have a proton in a uniform field between two parallel oppositely charged plates and the proton accelerates, the electric force acting on it stays constant seeing it is a uniform field and as a ...
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Why is the voltage of a battery equal to the emf?

We know that there is an electric field inside the battery that works against the moving electrons of a circuit. But there is also the chemical force of the battery that at some point become equal. ...
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Gauss Law for a Modified Coulomb's Law

A problem out of a certain popular book on electricity and magnetism dealt with the resulting electrostatic theory if Coulomb's law was replaced with the following equation: $$ \mathbf{F} = ...
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154 views

Coulomb's law and Gauss' Law

Which of these laws is more fundamental or forms the basis of electrostatics? I started off with Coulomb's law and then I studied Gauss' law. I was wondering which one is more universal? My professor ...
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How did special relativity change physicists views on the two prominent inverse square laws (ie Newton grav and Coulomb's law)?

On page 107 in Hartle's Gravity -- An introduction to Einstein's General Relativity, he says the following With the success of special relativity it became apparent that the Newtonian theory of ...
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60 views

How do photons mediate (or create) a force?

Is there a somewhat intuitive explanation as to why the exchange of a photon between two particles causes a force between those particles? Is there a difference in the way massless and massive ...
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32 views

What's the Relation between Potential of mechanics and electricity?

As we know that for a conservative force field, there is associated a Potential with the force. But we know there is a potential in electricity (That's voltage). My question is that is there any ...
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118 views

Origin of the Lorentz force from the point view of relativity?

I'm a physicist, when I'm working on the quantum spin hall effect, I recollected the high-school knowledge on Lorentz force and try to explain the origin of it, but didn't get it in the first glance. ...
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My electrophorus doesn't work

I have failed in generating charge using electrophorus. The charging material was a balloon rubbed with hair until it became very full of static, as well as a small piece of Styrofoam rubbed with the ...
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233 views

Rigorous proof of Gauss' law for an arbitrary charge distribution from Coulomb's law

Most of the books about electromagnetism prove Gauss' law for a point charge in vacuum: $$ \Phi = \int_{\Sigma} \mathbf{E} \centerdot d \mathbf{S} = q/\epsilon_0 $$ and then simply state that for ...
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Repulsive force between same charged plates?

I understand that the attraction force between parallel plates of capacitor is the derivative of stored energy with respect to distance of the plates. But how could we find the repulsive force between ...
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84 views

Gauss's Law of Electric Field how it actually works? & How Gauss derived it?

I want to know how Gauss derived his equation of Electric Field. Did he derive it from Coulomb's law? I don't think so. Please tell me some details about how this law works? inside a Gaussian ...
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Galilean and Lorentz Covariance in Julian Schwinger's book Electrodynamics

In the book Electrodynamics (pp. 8-11) Julian Schwinger "derives" (in this special case) the complete Maxwell equations from the Coulomb potential using only the Galilean transformation $$ ...
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Is it equivalent to derive Gauss's law from discrete and continuous source distributions?

I've seen two derivations for Gauss's law in electrostatics. The first assumes a discrete charge distribution, the second a continuous one: Use superposition $$\vec{E}=\sum_{i=1}^n\vec{E}_i,$$ so ...
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A query regarding constant $\frac{1}{4\pi \epsilon_{0}}$ in Coulomb's Law [duplicate]

In our physics class we were discussing about Coulomb's Law and equation for the electrostatic force between two points: $$F_{e}=\frac{Q_{1}Q_{2}}{4\pi \epsilon_0 r^2}$$ From the equation a query ...
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If the field concept was invented by Faraday, then how did Newton interpret the $g$?

This is Newton's law of universal gravitation. $F=G\frac{m_1.m_2}{r^2}$ Gravitational field $g$ is derived from this formula $g=G\frac{m_1}{r^2}$ This is named gravitational "field" strength. If ...
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What are some most advanced theories explaining why same charge repel, opposite charge attract? [duplicate]

It is the holidays with a lot to think about. One of the thing that I couldn't get out of my mind was something I read in Stephen Hawking's "Brief History of Time". In it, he described the repelling ...
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Why according to Hund's first rule all electron with same spin should occupy orbitals when partially filling?

I get that because of coulomb repulsion initially all the electrons will not occupy the same site but will single occupy the orbitals.But while doing so how do they know to keep their spins aligned ...
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Isn't the Coulomb interaction a photon interaction between two charges?

Isn't the Coulomb interaction a photon interaction between two charges? if yes then what does the following text mean? (Many-particle Physics by Gerald D. Mahan.)
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Is my representation of $\varphi$ Work function correct?

I am a middle-school so my understanding of physics may not be as solid as you professional physicists but never the less thought its worth a try to learn more. I read about photo-electric effect by ...
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Coulomb's Law in the presence of a strong gravitational field

I was under the impression that the $1/r^2$ falloff of various forces were because of the way the area of a expanding sphere scales. But that strict $1/r^2$ falloff would only be globally true in a ...
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69 views

Forces on moving charges

I want to know what are the total forces on a moving charge due to another charge. I heard that moving charges is the cause of all magnetism.So what I think is that if we have a charge in motion ...
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79 views

How does the force between two charges becomes zero?

In case of Coulombs law, $$ F=k\frac{q_1q_2}{d^2} $$ So, if $F=0$, then $q_1q_2$ must be 0. Is this true?
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Is many-body Hamiltonian valid in strong-correlated system

Condensed-matter textbook often states that there is a many-body Hamiltonian $$ H= \sum_i \frac{ p_i^2}{2m_i} + \sum_{i>j} V_{ij} \tag{1} $$ where $V_{ij} = Z_i Z_j/r_{ij}$. This Hamiltonian ...
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Using Coulomb's law to solve for a continuous charge distribution [closed]

I have been trying to evaluate this specific integral and have been completely stuck. $$\frac{1}{4\pi \epsilon_0} \int^L_0 \frac{2\lambda z}{(x^2+z^2)^\frac{3}{2}}dx.$$ I am a freshman and have been ...
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90 views

The classical hydrogen atom

Suppose we want to analyze a hydrogen atom using purely classical mechanics. This obviously is not exactly how things work - quantum mechanics plays a huge role and probability distributions are ...
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Electric field due to continuous volume charge distribution [duplicate]

Since the Electric field at point (0,0,z) is $$dE = \frac{\rho vdv}{4\pi\epsilon_0R^2}\hat{R}$$ $$\hat{R} = \cos\alpha \hat{z} + \sin\alpha \hat{\rho}$$ where $\hat{R}$ means unit vector $R$. ...
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Coulombs Law step by step help

How do you calculate the the magnitude of the total force of three charges and also the angle it makes with the x-axis? Knowing the magnitude and also the 2d co ordinates of the charges. I have ...
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999 views

Zero divergence of Electric field

I'm trying to rigorously derive the integral form of Gauss's law from Coulomb's law and the divergence theorem. Arrive at $$ \oint\limits_{\partial V} E\cdot da = \begin{cases} \frac ...
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Why is the current in an electric circuit constant?

Considering electrostatics, suppose we have two charges of equal value and opposite sign and we put electrons along the road between them: We know that the electrical force or field is different from ...
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Can two electrons get ever so close as to touch each other?

My friend and I were studying for our EM test when we started to think about what happens to the electric field near an infinite line of charge. $$E = \frac{\lambda}{2\pi\rho\epsilon_{0}}$$ As you ...