# Questions tagged [maxwell-equations]

A set of four equations that define electrodynamics. They comprise the Gauss laws for the electric and magnetic fields, the Faraday law, and the Ampère law. Together, these equations uniquely determine the electric and magnetic fields of a physical system. DO NOT USE THIS TAG for the Maxwell-Boltzmann distribution, or the thermodynamical equations known as Maxwell's relations.

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### How does the electric field instantly reflect the divergence in a system?

Suppose I have a decreasing charge ρ at the center of a sphere being carried away by a wire out of the sphere at a uniform rate. By Gauss law, the surface integral of the electric field normal to the ...
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### Topological current in (2+1)D spinorial electrodynamics

Giving the coupled Dirac equations for $\psi$ and its conjugate $\bar{\psi}$ in 2+1: \begin{align} (i\gamma^\mu\partial_\mu-m)\psi&=qA_\mu\gamma^\mu\psi,\\ \bar{\psi}(i\gamma^\mu\partial_\mu+m)&...
1 vote
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### Hertzian Dipole: Why is there no longer a phase shift at $\frac\lambda2$? [closed]

Today we learned about the Hertzian Dipole. Out teacher told us that the length of the wire connecting the two capacitor plates is $l=\frac\lambda2$. He also stated that there is a no more phase shift ...
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### What is the electric field around an inductor?

This question comes from this Walter Lewin video at 35:00 where he says "I'm going to confuse you even more" (and I suppose he somewhat succeeded). Walter Lewin claims there is an electric ...
1 vote
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### Electric field beyond its simple definition of force per unit charge

I read this from Div, Grad, Curl and All That: The second reason for introducing the electrostatic field is more basic. It turns out that all classical electromagnetic theory can be codified in terms ...
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### Magnetic field around a current carrying wire with changing magnitude of current

The magnetic field around a long, straight current carrying wire is given by $B = \frac{\mu i}{2\pi r}$ which comes from Maxwell's fourth equation,assuming that there is no changing electric flux as ...
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In Ideal MHD, we assume the plasma to be force-free: $$\vec{E} = - \frac{1}{c}\left(\vec{v}\times \vec{B}\right)$$ But the Euler equation of motion is written as: $$\rho \frac{d\vec{u}}{dt} = \vec{j}\... 0 votes 1 answer 63 views ### Electrical and Electronic circuits simulation using Maxwell's equations How can the Maxwell equations be used for developing exact mathematical model of electrical and electronic circuits? 0 votes 0 answers 28 views ### Choice of origin for Induced Electric Field due to Magnetic Field Consider a region of a magnetic field varying uniformly with space such that change of magnetic field is along z-axis of a cylindrical coordinate system. Now, this will obviously induce an electric ... 0 votes 1 answer 35 views ### EMF Generated according to Faraday's Law According to Faraday's Law, due to a relative movement between the current carrying loop and the magnetic field, an EMF is induced in the loop causing a current flow. However, according to Maxwell-... 0 votes 2 answers 65 views ### In Maxwell's equations concerning dielectric materials , does the electric field represent the external electric field or the net electric field? Let's assume we have dielectric material and we apply an external electric field that acts on it (let's call it Ex ) . As a resault we get dipoles who in turn create another electric field (let's call ... 4 votes 1 answer 84 views ### How would you calculate (numerically) the shape of the electromagnetic waves emitted by an accelerating charge? I am interested in trying to create an animation showing an accelerating charge emitting electromagnetic waves that is physically accurate. Writing the code is not what I am worried about, however, I ... 1 vote 1 answer 82 views ### Inconsistency with Bio-Savart Law and Ampere's law In David J Griffiths textbook "Introduction to Electrodynamics", he states that the strength of the magnetic field a distance s away from a steady current along a long wire is$$ B = μ_0(... 43 views

### Asking about a clarification of a rather strange notation of a Yee Grid used for discretizing Maxwell's Equations

The thesis I am following requires me to discuss a rather strange formulation of a Yee grid used to discretize Maxwell's equations in order to solve them numerically mentioned in a research paper. The ...
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### Why are the electric and magnetic fields not determined by the first two Maxwell equations (understanding the Landau volume 2 book explanation)?

(The question is short but the context is long) In Chapter 3 of Volume 2, Landau derives the equation of motion of a charged particle in an electromagnetic field as follows. Consider a charged ...
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### How does displacement current relates to capacitive coupling?

Im reading make: electronics, and I have investigated a little bit about displacement current and how a change in electric flux can create a magnetic field in a vacuum. A can understand that, however ...
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### Doubt regarding microscopic averaging of current density

We know that when averaging the velocity vector field of a current distribution over a particular volume, we get velocity fields that are slow varying over macroscopically small / infinitesimal ...
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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 ...
According to Maxwell's equations, if we take a circle close to a positive charge (such that the charge is not inside the circle), the divergence of the circle should be $0$ (because there is no ...