Questions tagged [electromagnetism]
For questions about Electromagnetism - a branch of Physics involving the study of the electromagnetic force, a physical interaction that occurs between electrically charged particles
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Who postulated the first Lagrangian for electrodynamics?
I am trying to find who first translated Maxwell's equations and Lorentz's force into the Lagrangian formalism. It seems a very straightforward thing to do if you know enough of electromagnetism and ...
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Tesla tried to replicate Hertz's experiment?
Jan Rak, in his NAMI-tech SEM 2023 lecture (@12:53), claims:
However, at the time Nicola Tesla […] was trying to replicate the Hertz experiment, and he was unsuccessful. He discovered some other ...
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Translation of Cabeo's Philosophia magnetica
Is there a translation of Niccolò Cabeo's work Philosophia magnetica into English (or other modern language)? The original text in Latin is available for example here but I can't find any translation (...
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"Équation de Maxwell-Thomson"
In French, Gauss' law for magnetism (no magnetic monopoles) is, sometimes at least, referred to as Équation de Maxwell-Thomson. What is the historical justification of this?
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Question on Gauss's geometric interpretation of "spherical functions"
In the physics chapter of his biography of Gauss, W.K. Buhler writes the following:
Expansions into series are frequent and important in potential theory. So it does not come as a surprise that ...
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Early sources for surface and bound charges in polarization
I am looking for early sources (references) to the analysis in electrostatics where the polarization vector is rewritten in terms of bound charges and a surface polarization charge.
In terms of what I ...
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How and by whom was the magnetic term in the Hamiltonian first derived?
The Hamiltonian of a charged particle in a magnetic field is: $$H=\frac{1}{2m}(\frac{h}{2\pi i}\nabla-qA)^2+q\phi$$
Can anybody help me find out when, how and by whom was it first derived?
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Why did Maxwell predict radiation pressure?
I know that Kepler thought based on comet tail that light might exert pressure (although is the Solar wind not also involved?) but did Maxwell's prediction stem from newer observations or from perhaps ...
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Granville Wood's Telegraph -- do we know the data rate and range?
I realize this is more a history of engineering question but I do not see a SE devoted to this so I thought I would ask here.
https://suiter.com/granville-woods-railway-telegraphy-patent-no-373383/ ...
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A question concerning the history of Maxwell's equations
So I am writing my thesis around the Maxwell equations, in one part I saw to speak about their history. The issue is, I found conflicting pieces of information as to who enunciated the laws first.
Let'...
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When were the foundations of vector calculus laid?
Upon some browsing I find from many online sources that vector calculus was created in the time of late 19th century by Gibbs and Heaviside, but Gauss, Green, Stokes, etc., who lived much before that, ...
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What are the equations of Electric Gravity Lorentz derived, and what is the paper in which they are found?
I read on a blogpost that Lorentz built a mathematical model of gravity, but with an assumption that it arose from electrical origins. I tried googling for more information and could not find anything ...
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The etymology of "radio waves"
The word "radio" originates from "radius", which in turn came from "ray". That's why "radius" means any line from a central focal point to any directions.
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Who gave right hand thumb rule for circular loop of current conducting wire?
To find magnetic field due to current conducting straight wire we have Maxwell's Right hand thumb rule, Which says "Put your right hand thumb in the direction of current then curled fingers shows ...
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Who gave right hand thumb rule for circular loop of current conducting wire?
To find magnetic field due to current conducting straight wire we have Maxwell's Right hand thumb rule, Which says "Put your right hand thumb in the direction of current then curled fingers shows ...
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Why was the idea of "field" introduced?
I read in my Physics textbook that the notion of Electric fields are useful "when we have to deal with time dependent Electromagnetic phenomenon since no information can travel faster than light&...
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Component form of the fourth Maxwell's equation
I am doing an introduction to Maxwell's equations, and it is said that originally the equations were in component form. Can anyone help with the derivation of the fourth equation? I have checked many ...
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How did Gauss come up with his law?
Why did it seem at the time of Gauss that the quantity we get by multiplication of electric field with the area would have some value to it? That is what was the motivation for Gauss to find the flux ...
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Did Maxwell discuss charge quantization?
I once read in Wikipedia that James Clerk Maxwell included the possibility that charge could be both quantified and continuous. Since the electron hadn't been discovered in 1873, does Maxwell discuss ...
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Was Nikola Tesla aware of Maxwell's equations?
Was Nikola Tesla aware of Maxwell's equations or Heinrich Hertz's experimental proof of the former when he worked on his radio device invention?
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How were the values of permeability and permittivity derived?
Do you know how the values were measured and if they where determined by particular conditions/ restraints? They can be put to 1 (or to any values, I suppose); what escapes me is why 1/ε × μ must be ...
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How has the modelling of classical electrodynamics changed since Maxwell?
Maxwell published his Treatise on Electricity and Magnetism in 1873, 150 years ago; before the discovery of quantized charges, special relativity, quantum field theory etc. How has the mathematical ...
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Why is electric potential denoted by $\phi$?
I haven't found any explanation for it, and I'm curious.
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Notation of Poynting vector
I know that the Poynting vector is defined as the cross-product $\vec{E}\times\vec{H}$ and that is "usually" denoted by $\vec{S}$ or $\vec{N}$.
I wonder if there is a particular reason for ...
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Did Hertz discover the concept of frequency and if so, how did Doppler think of frequency?
I may not be understanding what a "Hertz" is but it seems to simply be one cycle per second. But would not Doppler have understood what frequency was decades before Hertz? Or was Hertz just ...
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Had Albert Einstein tried to use the Galilean transformation on Maxwell's equations before AE's Special Theory?
I am looking for what motivated Albert Einstein in the direction of his Special Theory. I have read that it is unclear if he was set on that path by the Michelson-Morley experiments. Was AE aware ...
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Whatever happened to parageometrical optics of diffraction?
In 1950, Giuliano Toraldo di Francia published a paper [1] with the title "Parageometrical Optics" followed by several other papers on the subject, I dare say culminating in a beautiful ...
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Why is the magnetic force on a current-carrying wire sometimes called the Laplace force?
Educated in the UK, I've been used to calling the force on a current-carrying wire in a magnetic field 'the motor effect force'. But I'm increasingly aware of another (less clumsy?) name for it: 'the ...
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Demystifying Nikola Tesla: Scientifically sound, historically accurate biography
As any physicist knows, a lot of amateur science afficionados out there bring up Nikola Tesla in rather fantastical ways. There are indeed a few reasons for his near mythical status in popular culture,...
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How was it determined that charge and current were made of the same stuff?
Even in my earliest physics course we took for granted that charges are made of electrons (or their absence) and currents are due to the motion of electrons. But the electron is a very modern concept ...
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Who discovered the electric potential?
Wikipedia says that the magnetic vector potential was discovered by Neumann in 1845, by Weber in 1846 and Lord Kelvin in 1847. It does not mention who discovered the electric scalar potential.
Hence ...
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de Broglie's conception of the electron
I've been working on de Broglie's thesis (English PDF, Original French PDF) for a course, and I've found something that's been bothering me. My training is in Physics, and so I'm not particularly ...
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Which scientist(s) first measured the elementary charge and how did they do it? [duplicate]
I would be grateful if anyone could shed some light on these questions.
Which scientist(s) first measured the elementary charge? If it wasn't measured in a straightforward experimental setting, and ...
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How did Stern or Gerlach, of Stern-Gerlach experiment, create individual silver atoms? How were they accelerated?
How, a century ago, could Stern and/or Gerlach KNOW that they had created single silver atoms?
How were they moved, or accelerated?
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Bohr-Kramers-Slater (BKS) theory and energy conservation only on statistically basis
I was reading Wikipedia article on Bohr-Kramers-Slater (BKS) theory, https://en.wikipedia.org/wiki/BKS_theory. I encountered two interesting points and need your help to understand the reasons behind ...
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Were there any contributions to thermodynamics and electromagnetism from Medieval Islamic science?
The Medieval Islamic world, between 8th to the mid 13th century, is known for its developments in academic knowledge. Particularly in astronomy. Many stellar objects still derive their name from ...
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How did Gauss, Ampere and Biot-Savart derive their laws?
Gauss' law for electricity and magnetism, Ampere's law and Biot-Savart's law — all of these laws are crucial for understanding electromagnetism and Maxwell's equations.
But I want to know how each of ...
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When was the earliest speculation that gravity and electromagnetism had a unified description?
In 1786, Coulomb announced his law that showed that the electromagnetic force between two charged sources followed an inverse square law.
Given that gravity followed a similar law, did anyone suggest ...
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Why is the constant of magnetic fields called permeability and that of electric fields called permittivity? [closed]
Basically the title, I found it weird that we use two different names for each fields. What were the reasons for doing so, historically speaking?
user12582
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When was "Faraday's Law of Induction" first expressed in a quantified form?
An often used definition of "Faraday's Law of Induction" goes something like this (found in Wikipedia)
The electromotive force around a closed path is equal to the negative of the time rate ...
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Validity of Maxwell's equations in the aether's reference frame
If Maxwell's equations were experimentally found on Earth such as Faradays law, coulombs law , and worked in the Earth's frame of reference, then why did people believe them to be valid in the aether'...
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Who invented the quadrupole lens for charged particles?
I am wondering who actually invented the (magnetic) quadrupole lens or who used it for the first time. I have found some papers from the 50s and 60s about more complicated systems based on Quadrupoles,...
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Why is wave guide theory developed so long after Maxwell's work was published?
When some fundamental new theory is published, derived work will be done "instantly", example from quantum mechanics:
1926 Schrödinger equation
1927 The first application of quantum ...
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What is a Heaviside rational current element?
This terminology seems to be referred to a notion invented in an old book of Oliver Heaviside [1]. What is it and why the Biot-Savart law is not unique unless it is applied to a Heaviside rational ...
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How was charge to mass ratio measured via electrolysis in 19th century?
I think this question is useful to know how sir J.J.Thomson inferred from his experiment that the electron had to be 1700 lighter than hydrogen, as he declared in his Nobel Lecture of 1906:
Before ...
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How and for what purpose did Lorentz come out with his "electron model"?
Who suggested to him the idea that charge wasn't really some excess or defect of "electric fluid", but rather something carried by a particle?
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How did physicists deal with the variance of electromagnetism before special relativity?
I am trying to write a paper on how Einstein's special relativity (SR) essentially saved electromagnetism for high school and am confused on how the following two problems were solved.
How did ...
OVERWOOTCH
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Names of the electromagnetic units in SI
The unit of electric charge is the coulomb, named after Charles Augustin de Coulomb. This makes sense because Coulomb's law talks about the force between two charges. Likewise, it also makes sense to ...
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Are there any descriptions of the reluctance motor invented by W.H. Taylor in the 1800's?
I could not find any descriptions of the first motors of W. H. Taylor in Wikipedia of any reference, history or circumstances surrounding its invention. Apparently the motor was never used for any ...
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Where exactly did George Brown publish the first paper about Turnstile antennas?
In its most basic form the Turnstile antenna is two half-wave dipole antennas that are perpendicular and driven 90 degrees out of phase. For a recent review see Crossed Dipole Antennas: A review (also ...
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