Maxwell Definition and 454 Threads

  1. E

    Material definition problem in ANSYS Maxwell

    HI Guys, I am getting an error in Ansys Maxwell that says Maxwell2d solver, process solver2d: Internal Solver Error: 'In the Material: M270-35A_12 , the SLOPE of the End Two Points in this BH curve is 56519.1, which is more than 2 times of Mu0; This may lead to a non-physical solution...
  2. Twigg

    Book Hunt: Statistical Treatment of Macroscopic Maxwell Eqns

    Hello all, Jackson Ch. 6 (3rd edition) tells the reader to look at de Groot for a statistical mechanical derivation of the macroscopic Maxwell equations. I figure he means "Foundations of Electrodynamics" by S. R. de Groot. I requested that book be sent to my school library on loan, but I was...
  3. Bharat

    ANSYS MAXWELL SIMPLORER Solution Error

    Dear all I am doing a simulation of a 3 phase transformer. I am adding the excitation using external circuit in Simplorer , I am getting these error ! Can somebody comment on the error . An external simulator couldn't be setup for simulation. (12:01:33 PM May 02, 2017) Simulation completed...
  4. C

    Solutions of wave equation but not Maxwell equations

    Maxwell equation in absence of charges and currents are $$\nabla \cdot \bf{E} = 0 \\ \nabla\cdot B=0 \\ \nabla \times E=-\frac{\partial B}{\partial t} \\\nabla \times B=\mu \epsilon \frac{\partial E}{\partial t}$$ Wave equation is $$\nabla ^2 \bf{E}=\mu \epsilon \frac{\partial^2...
  5. L

    Maxwell eqs. - integral formulation in dynamics

    The integral formulation of Maxwell equations, for example the one called "Gauss' theorem", see the first equation here: https://en.wikipedia.org/wiki/Maxwell's_equations is still valid in dynamics, with rapidly varying sources? We know that a rapidly varying charge here gives a flux of an...
  6. P

    Is the Energy of Gamma Rays and Radio Waves Equivalent with Equal Amplitudes?

    According to the old thery of light the energy carried by by a wave is proportional to the amplitude of the electric field not to the frequency as Planck proposed, so an eletromagnetic radiation in the gamma spectrum carry the same energy as a radio one if their amplitude is the same? They only...
  7. JulienB

    Verifying a macroscopic Maxwell equation

    Homework Statement Hi everybody! I have trouble understanding the following problem, hopefully somebody can help! Show that the electrostatic potential ##\phi(\vec{x}) = \phi_\text{free} (\vec{x}) + \phi_\text{ind} (\vec{x}) = \frac{1}{4 \pi \epsilon_0} \bigg( \int d^3 x'\...
  8. P

    Does the first maxwell equation apply only....

    For static electric fields? does it apply also for a generic electric field? Let's say, moving charges inside a closed surface? If there are charges accelerating in a closed surface a part of the electric field is due to the charges, and a a part is due to the fact that the charges acceleration...
  9. F

    I D'Alembert equation and Galilean transformation

    The D'Alembert equation for the mechanical waves was written in 1750. It is not invariant under a Galilean transformation. Why nobody was shocked about this at the time? Why we had to wait more than a hundred years (Maxwell's equations) to discover that Galilean transformations are wrong...
  10. J

    Plasma Book with Maxwell equations in a plasma?

    My main goal is to understand plasmons, for that I have been told that the theoretical background is Maxwell equations in a plasma. Do you know any book with these equations? Thanks!
  11. E

    Ansys Maxwell problem -- band around coil is a difficult geometry?

    Hey Guys, through the past years you helped me a lot. But now i have to ask my first question. I am simulating a solenoid, a very easy one, with a core and a coil. And a translational band (2mm). The only problem is, that i cannot put the band correctly because my solenoid is in a housing, the...
  12. stephen8686

    How did Maxwell find the speed of light

    According to this video I was watching Maxwell was looking for the speed of EM waves and just divided coulomb's constant by the magnetic constant and then took the square root and that was the speed of light. √(Ke/μ0)=√(9e9/1e-7) = 3e8m/s So why is this a thing? I just don't understand why it...
  13. nafuturo

    How Do You Solve These Electromagnetism Problems?

    https://postimg.org/image/lg27z8ngn/ 1. Homework Statement in the first one. I need to find the electrical force in the second one. Lorentz force which exerts the wire on the other element third. Magnetization (M) for Nickel quarter. Electromotive force induced on the dipstick Translate...
  14. Mayan Fung

    Problems related to Maxwell relations

    Homework Statement Given the entropy of a system : $$ S = AU^αV^βN^{1-α-β} $$ The problem requires me to write $$ (\frac{∂T}{∂U})_{V,N} > 0,  (\frac{∂P}{∂V})_{U,N} < 0, (\frac{∂μ}{∂N})_{U,V} > 0$$ to find the mathematical constraint of α and β Homework Equations dU = TdS - PdV + μdN The...
  15. E

    A Maxwell field commutation relations

    Maxwell field commutation relations I'm looking at Aitchison and Hey's QFT book. I see in Chapter 7, (pp. 191-192), they write down the canonical momentum for the Maxwell field A^\mu(x): \pi^0=\partial_\mu A^\mu \\ \pi^i=-\dot{A}^i+\partial^i A^0 and then write down the commutation...
  16. D

    Chemical thermodynamics, entropy, Maxwell relation and Z

    Homework Statement A gas obeys the equation of statez=1/(1-b(molar density)) What is the molar entropy change of expanding this gas from a volume of 1 dm3 to 2 dm3 at a temperature of 300 K, given b = 0.2 dm3? Calculate your answer to three significant figures and select one answer from the...
  17. G

    I Differential form of Gauss' law: All three terms the same value?

    Hi. Is the Maxwell equation $$\nabla\cdot\vec{E}=\frac{\rho}{\varepsilon_0}$$ even true in the stronger form $$\frac{\partial E_i}{\partial x_i}=\frac{\rho}{3\cdot\varepsilon_0}\enspace ?$$ I guess not, since I haven't found a source suggesting this. But shouldn't the isotropic electric field...
  18. K

    Calculating velocity using maxwell distribution

    Homework Statement Consider helium as ideal gas with a Maxwell distribution of speeds. (a) Investigate the maximal value Fmax at the peak of the Maxwell distribution F(v): Calculate this value for He at T = 300 K and at 600 K, and for N2 at 300 K b) For He at 300 K, obtain speeds v1...
  19. T

    No slip condition in an ideal fluid- Perpendicular pressure

    The no slip condition has been described as the adhesion of a fluid to a solid surface setting the relative fluid velocity to zero - cohesion (viscous stress) between fluid elements spreads evenly the velocity gradient through the boundary to the free stream. This also infers that the pressure...
  20. D

    Determine the direction of magnetic field from Maxwell eqs?

    Hi! My high school physics tells me using right hand grip rule to determine the direction of magnetic field induced by a current carrying wire, but I wonder whether I can deduce the direction merely from Maxwell's Equations? Suppose now we have a current density in cylindrical...
  21. F

    Maxwell's equation has well defined divergence?

    Homework Statement How to I explain that maxwell's equation has well defined divergence Homework Equations All four EM Maxwell's equation The Attempt at a Solution I discussed it by showing one of the property of Maxwell's equation that is the Divergence of a Gradient is always zero (With...
  22. G

    Maxwell and the speed of light

    Einstein said that the speed of light is constant for all observers. When Maxwell derived that the speed of light in the ether was 299,792,458 m/s could he or did he surmise that the speed of light is constant for all observers (regardless of the motion of the source)?
  23. P

    Liénard–Wiechert potentials: Local or Material derivatives?

    If I took a charged particle and accelerated it, that acceleration would have an effect on charges potentials, allowing for the radiation of electromagnetic waves. This acceleration would be local to a point in spacetime and the observed potentials would depend on the frame of reference of the...
  24. P

    Constant Charge/Current Densities with Accelerating Charges

    In classical physics, when electric charges accelerate, they are expected to radiate. Electromagnetic waves, are by their nature the result of changing electric and magnetic fields. But is it possible to have acceleration of charges without having changing electric and magnetic fields? One...
  25. S

    Maxwell equations from tensor notation to component notation

    Homework Statement Verify that ##\partial_{\mu}F_{\nu\lambda}+\partial_{\nu}F_{\lambda\mu}+\partial_{\lambda}F_{\mu\nu}## is equivalent to ##\partial_{[\mu}F_{\nu\lambda]}=0##, and that they are both equivalent to ##\tilde{\epsilon}^{ijk}\partial_{j}E_{k}+\partial_{0}B^{i}=0## and...
  26. GauravU

    Open circuit test of 3 phase transformer in Ansys Maxwell

    Hi all, I am designing a three phase 11000/433 Volts Delta/Star 50 Hertz transformer in Ansys Maxwell. It has 792 turns in 6 layers on HV side (132 turns per layer) and 18 turns in 2 layers (9 turns per layer). The resistance as I have calculated is 0.1325 ohms per phase of HV winding and 5.57...
  27. olgerm

    Maxwell equations in terms of potentials

    These are Maxwell´s equations in potential formulation: ∇2φ = DIV(grad(φ)) . Am I right? ∇2A = ROT(ROT(A))=ROT(B)=grad(DIV(A))-Laplace(A) . Am I right? In coulomb gauge in every point and at any time DIV(A)=[PLAIN]https://upload.wikimedia.org/math/4/4/1/44131cc26bd9db464d0edb7459ccca84.png...
  28. S

    Lorentz invariance of Klein-Gordon eqn & Maxwell Lagrangian

    Homework Statement 1. Show directly that if ##\varphi(x)## satisfies the Klein-Gordon equation, then ##\varphi(\Lambda^{-1}x)## also satisfies this equation for any Lorentz transformation ##\Lambda##. 2. Show that ##\mathcal{L}_{Maxwell}=-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}## is invariant under...
  29. C

    Maxwell's Electrodynamics: The Unusual and Incomplete Theory by Duhem (1902)

    "Maxwell's electrodynamics proceeds in the same unusual way already analyzed in studying his electrostatics. Under the influence of hypotheses which remain vague and undefined in his mind, Maxwell sketches a theory which he never completes, he does not even bother to remove contradictions from...
  30. T

    Integration of Maxwell speed distribution function

    Homework Statement Show the steps needed to obtain the equation for average molecular speed, cavg=√8RT/πM from the integral (from negative infinity to infinity) ∫v*f(v)dv where f(v) is the Maxwell distribution of speeds function f(v)=4π*(M/2πRT)1.5v2e-Mv2/2RT M is the molar mass of the...
  31. Teameister

    Work done moving charge near a line of charge

    Homework Statement How much work (in J) is required to bring a charge of 2 microC from the point {2*6.8,-7,2*1.1}cm via the point {10,20,1}cm to the point {-3*6.8,3.4,-3*1.1}cm, in a medium with relative permittivity of 3.7, near a line charge along x=6.8 cm, z=1.1 cm, with charge density +329...
  32. J

    Algebra Looking for a book on Quaternions

    Hello everyone, Lately, I have been reading and studying the Maxwell's https://es.wikipedia.org/w/index.php?title=A_Treatise_on_Electricity_and_Magnetism&action=edit&redlink=1 https://es.wikipedia.org/w/index.php?title=A_Treatise_on_Electricity_and_Magnetism&action=edit&redlink=1 Thanks for...
  33. P

    Fermat's principle can be derived from Maxwell equations?

    As we know, the Fermat's principle states: Light takes the path of least time. I wonder whether Fermat's principle can be derived from Maxwell equations. If it can, then Fermat's principle is included in Maxwell equations, or Fermat's principle is not an independent postulate.
  34. J

    When can I use Helmholtz equation for electromagnetics

    The complete Maxwell wave equation for electromagnetic field using the double curl operator "∇×∇×". Only when the transverse condition is hold, this operator can equal to the Laplace operator and form the helmholtz. My question is what's the condition can we use the helmoltz equation instead of...
  35. A

    Gibbs Free Energy, Maxwell Relations

    Homework Statement We have a Gibbs Free Energy function G=G(P, T, N1, N2) I am not writing the whole function because I just want a push in the right direction. Find expressions for the entropy, volume, internal energy, enthalpy and chemical potential. Homework Equations Maxwell Relations...
  36. S

    More ebooks about Maxwell relations of Thermodynamics

    I'm learning about Maxwell relations of Thermodynamics, but it's difficult for me to find more books about this in Vietnamese. So, I want to ask you about some english ebook about this. Thanks a lot!
  37. wololo

    [itex](\frac{\partial U}{\partial P})_T[/itex] derivation

    Homework Statement Homework Equations Maxwell relations The Attempt at a Solution Here is how I proceeded. Am I allowed to go from line 1 to 2? It almost seems too simple. dU=TdS-PdV \\ (\frac{\partial U}{\partial P})_T=T(\frac{\partial S}{\partial P})_T-P(\frac{\partial V}{\partial P})_T...
  38. AwesomeTrains

    Question about the derivation of the energy momentum tensor

    Hey I'm trying to follow the derivation given here: http://lampx.tugraz.at/~hadley/ss1/studentpresentations/Bloch08.pdf Homework Statement As it says in the pdf: "Based on Noether's theorem construct the energy-momentum tensor for classical electromagnetism from the above Lagrangian. L=-1/4...
  39. wololo

    What is the solution for finding F in terms of T and V without integrating?

    Homework Statement Homework Equations Maxwell relations The Attempt at a Solution I have an attempt at a solution, but I am not sure if I can replace the integral of dT in the helmholtz equation by the T I found using the internal energy. Does this make sense? Thanks
  40. V

    Maxwell distribution of relative velocities

    I want to calculate the distribution function for the relative velocity v_r = v_1 - v_2 of two particles. Each particle velocity follows the Maxwell distribution for velocities. They have the same mass and temperature. Can I just multiplicate the Maxwell distributions of the two particles (and...
  41. T

    Layman explanation of some simple EM equations

    So its been a while since I studied maxwells equations, anyway: So From my ignorant perspective, trying to derive conceptual meaning from these, I can see that the time dependant study there is some conductivity x the partial differential of the magnetic vector potential plus the cross product...
  42. G

    Problems solvable by thermodynamics of information

    Hello, I need to work on the thermodynamics theory of information, but I can't find real applications aside from the resolution of the maxwell's demon and the szilard engine. I would need more applications... Any idea?
  43. G

    Why Use Plane Waves to Solve Maxwell's Equations?

    When finding solutions to Maxwells equations we always cosider the case of a plane wave. But are plane waves real/physical solutions we can consider in real life? My guess is not because it is required to propagate infinitely. So why do we use plane waves to solve Maxwell's equations?
  44. G

    What is this version of the wave equation?

    I came across this expression for the wave equation: \nabla^2E + \mu\sigma\frac{\partial{E}}{\partial{t}} - \frac{n^2}{c^2}\frac{\partial{E}}{\partial{t^2}} = 0 My question is what kind of medium is it for/where did it come from?
  45. Luminescent

    Who Derived the Value of Magnetic Permeability in a Classical Vacuum?

    Who is credited for deriving the value of magnetic permeabilty in a classical vacuum? How would one go about sourcing information in relation to such a value?
  46. mr.93

    Maxwell 2d (ANSYS): Bldc motor simulation

    Hi all I have few questions in bldc motor simulation in maxwell 2d: - I need help in loss calculation,I exported a bldc motor in rmxprt to maxwell 2d after entering core properties and w/kg data in 50hz,in 2d checked stator and rotor in set core loss and checked (consider core loss effect on...
  47. M

    Maxwell fourth equation incorrect?

    Hi all this question seems to be silly but i want to where i am wrong. Maxwell was made modification in Amperes law curl H=J and he added new quantity displacement current Jd, reason was that Div.J=0 (true in DC current but not in AC charging capacitor). but if i say Div J=0 in capacitor...
  48. densaface

    Why is the Lorentz force calculated in Ansys Maxwell so low?

    Why is the Lorentz force calculated in Ansys so low? According to the formula F=B*I*l, it is supposed to be at least 1000 times higher. The model is really simple: a magnetically conductive plate in a static magnetic field inducts the magnetic field from the surrounding space, which makes its...
  49. Z

    Why Maxwell and Kelvin-Voigt model fail to represent a solid

    Hi I m studying modelling the viscoelastic passive properties of vascular walls and there is question! Why does Maxwell andKelvin-Voigt fail to represent a solid? and also what steps are required from a numerical point of implementation point of view , are required to turn an elastic model...
  50. A

    Why is μ0 assigned an exact value in SI units?

    Hello all, While I understand the significance of natural units, I am wondering why, in SI units, we are able to assign μ0 an exact value. The speed of light is experimentally determined in m/s, and given the relationship derived from Maxwell's equations, we know that c^2 = 1/√(ε0μ0). Thus by...
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