# Questions tagged [classical-electrodynamics]

Classical electrodynamics is the discipline that studies electromagnetic phenomena – such as electric and magnetic fields, radiation, and the dynamics of charged bodies – in classical terms.

934 questions
Filter by
Sorted by
Tagged with
80 views

### Derivations of Maxwell equations

In my book of electrodynamics, the Maxwell equations are always used for specific conditions (electrostatics, magnetostatics, …). But nowhere I see a complete derivation of the equations. Maybe it ...
108 views

Maxwell's equations in the vacuum with electric permittivity $\epsilon_0$ and magnetic permeability $\mu_0$ are given as: $$\nabla \cdot \vec E = \frac{\rho}{ \epsilon_0}$$ $$\nabla \cdot \vec B = 0... 0answers 40 views ### Does Jackson's result for the vector potential of current loop correct? General form of Maxwell equation is given by$$ \nabla_\mu F^{\mu\nu} = 4\pi J^\nu $$where F_{\mu\nu}=\nabla_\mu A_\nu-\nabla_\nu A_\mu is the tensor of EM field. Then Maxwell equations can be ... 1answer 66 views ### Charged particle moving in magnetic field using cylindrical coordinate [closed] It's knowen that a charged particle take a helix trajectory in a uniform magnetic field B =B e_z I tried to study this problem using cylindrical coordinate and i get that$$F=q v ×B = m a$$in ... 0answers 157 views ### Maxwell stress tensor for electromagnetic wave Sorry if this is a naive question but I've been struggling in trying to proof this for a week. Consider an electromagnetic wave with wave vector \vec{k}=k\hat{n}, the Maxwell stress tensor can be ... 0answers 105 views ### Magnetic field \vec{A} as momentum potential I was reviewing some topics on electromagnetic field theory and I came across the following interesting assertion: the electromagnetic moment P_{EM}, which is defined in vacuum as:$$P_{EM}=\frac{1}...
12k views

[This question is Certified Higgs Free!] Richard Feynman in Lectures on Physics Vol. II Sec. 17-4, "A paradox," describes a problem in electromagnetic induction that did not originate with him, but ...
43 views

34 views

### Symmetry operations on an infinite uniform sheet of charge

My book has a section on symmetry operations. It says, (if the plane of charge is the yz plane) translation symmetry along the y-axis and z-axis implies that the electric field is constant if one ...
163 views

19 views

### What are Towsend Coeffiecents exactly? And are there any tables out there to look them up?

My question is expecially for the gamma coefficent, does it depend from the air? And further how the material of electrodes is involved in Paschen's Law (Electric Arcs)?
850 views

### Is Faraday's law of induction valid for a partial conducting loop?

If a conductive loop is partial or incomplete(wrt. $A$), is Faraday's law of induction still valid? $$\varepsilon = -\frac{\delta \Phi_B}{\delta t}$$ Intuitively it seems possible to define the ...
76 views

105 views

### Poynting theorem in Landau and Lifshitz’ field theory book

In Landau & Lifshitz’s The Classical Theory of Fields, in section 31, they have proved the Poynting theorem (equation 31.6) in its integral form. In the footnote on page 76, they mention We ...
344 views

### How does the Lorentz force work for all velocities

At small velocities, the lorentz force in the boosted frame is approximately $F' = q(E + 2v \times B)$, where the one for the rest frame is $F = q(E + v \times B)$. How is this invariant if the two ...
34 views

### Electrodynamics confusion - Hertzian dipole

I am studying a course in Electrodynamics and we are just covering retarded potentials and the Hertzian dipole. In my lecture notes, we have calculated the magnetic vector potential $A$ in the ...
101 views

### On the “Derivation of the Electromagnetic Lagrangian density”

In the most upvoted answer here : Deriving Lagrangian density for electromagnetic field, how do we know that equations (015) and (016) therein \boxed{\: \dfrac{\partial }{\partial t}\...