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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How did Weyl's 1918 paper; Gravitation and Electricity, influence classical physics?

The main-stream view seems to be that Weyl's 1918 paper Gravitation and Electricity was initially considered a failure for reasons first pointed out by Einstein. But these initial ideas were reapplied ...
Larry Harson's user avatar
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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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When was the ratio between electric and magnetic forces in an electromagnetic field established?

We know that the magnetic force on a particle moving in a magnetic field was found by J.J. Thomson in 1881, with a slight mistake, and then corrected by Heaviside in 1885 to $F_M = q\,v\times B$. Can ...
user157860's user avatar
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Who was the first to use the term field in physics?

Faraday, after drawing his lines of force in 19th century, is normally credited as the first to use the term field in physics. But... ... was not the term field used in the context of gravitational ...
Diracology's user avatar
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During the development of QFT was this theory actually used to build any invention like the MRI?

I have always wondered if the equations of quantum field theory were actually ever used in the production of some invention or device other than needed to make predictions about the Standard Model of ...
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How did Maxwell conclude that $\frac{\partial\bf E}{\partial t}$ was necessary to complete $c^2\nabla \times \bf B= \frac{\bf J}{\epsilon_0}\;?$

As we know $$c^2\text{curl}\;\bf B= \frac{\bf J}{\epsilon_0}$$ is incomplete & in many cases like capacitor give contradictory result against Law of conservation of charge. As Feynman writes; ...
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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 ...
user2554's user avatar
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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 ...
GedankenExperimentalist's user avatar
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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 ...
David Jonsson's user avatar
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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 ...
Philip Wood's user avatar
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What was defined first and how? The ampere or the vacuum permeability?

I've been looking up the history and evolution of the seven base units and am currently checking out the ampere. What I've found is that 1A is defined as the current in a wire which would experience a ...
SpectraXCD's user avatar
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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&...
Ankit's user avatar
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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?
Hans's user avatar
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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,...
Felix Kern's user avatar
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Who originally worked out the magnetic field produced by a solenoid and toroid?

Although, it seems very easy to find the magnetic field produced by a solenoid or a toroid, all we got to do is to make a suitable an Amperian Loop and take the $\mathbf B$ out of the integral and so ...
Knight wants Loong back's user avatar
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Feynman's statement about the importance of basic science

I remember reading in the line that Feynman saying if the best technicians were tasked to build a radio they would make longer and thicker cables and transfer message but it took a physicist to ...
crossingsymmetry's user avatar
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Who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$? Was it Maxwell or Neumann?

I have been trying to find out who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$. Was it Maxwell himself, or was it Franz Ernst Neumann who derived it? The ...
PG1995's user avatar
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Who introduced concept of capacitance matrix

We know of two ways of representing voltage-charge relations of an assembly of conductors: $V_j=\sum P_iq_i$ and $Q_j=\sum C_iv_i$ Who introduced these equations for the first time and though one can ...
Kutsit's user avatar
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Modification of Newtonian Gravity based on Maxwell's Theory

As is well-known, Maxwell's equations were already consistent with Special Theory of Relativity while the Newtonian law of Gravitation wasn't. It can be shown by solving the equations of Maxwell for a ...
ACat's user avatar
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Historical milestones in experimental "verification" that light is a electromagnetic phenomenum

This is a follow up question to How did Maxwell conclude that light is an electromagnetic wave? where the arguments of Maxwell were explained why he considered light as an electromagnetic wave. What ...
Julia's user avatar
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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'...
الفقير للعفو's user avatar
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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, ...
nickbros123's user avatar
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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'...
Kashmiri's user avatar
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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 ...
8cold8hot's user avatar
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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?
ric.san's user avatar
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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 ...
Sedumjoy's user avatar
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Are Gauss' electrodynamics laws for charge-charge interaction correct in the limit of low-speeds?

My question refers to a fragment on electrodynamics written by Gauss at around 1835. In this short note (see Gauss' Werke, volume V, p.617) Gauss wrote down a fundamental equation which describes the ...
user2554's user avatar
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Who first noticed that the radiation pressure formula $p=U/c$ agreed with $E=pc$ from special relativity?

Does anyone know behind stories? As it seems that $p=U/c$ was known before the advent of special theory of relativity, (Halliday, Resnick, Walker says that Maxwell derived this.) when $E=pc$ was first ...
Youngsub Yoon's user avatar
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Who first discovered and produced an alternating current?

What physicist first discovered or produced an alternating current and recognized it as such?
Geremia's user avatar
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Mutual induction in electromagnetic wave theory

Frequently when electromagnetic waves are taught, it is said that the change in electric field causes a change in the magnetic field, which then causes a change in the electric field, and so on and so ...
Julia's user avatar
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Was the pre-special relativity discussion a hot topic in the late nineteenth and early twentieth century?

We know that low-dimensional materials and topological materials are some of the current hot topics in Physics. Did this happen with the pre-special relativity discussions in the late nineteenth and ...
Caetes's user avatar
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1 answer
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Why is electric dipole moment represented by “p”?

"I recently came across a text where the electric dipole moment was represented as "d" instead of the more commonly used "p". The reason behind using "d" here is probably that "dipole moment" begins ...
A B's user avatar
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Relationship between electromagnetic and topological invariant

I read 17 equations that changed the world by Ian Stewart. This book provides information about the correlation between electromagnetic force and topological invariant. The idea of a topological ...
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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 ...
Geremia's user avatar
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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 (...
maxbo's user avatar
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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 ...
LDM's user avatar
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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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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 ...
Diffycue's user avatar
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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 ...
AYM Shahriar Rahman's user avatar
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How did Gauss and Lagrange derive Gauss law of Electrostatics

On Wikipedia, these two pages are mentioned :Lagrange and Gauss however I am an English speaker and can not comprehend any of the one, can someone provide the translated pages or shortly their line of ...
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How did Reginald Fessenden realize that spark-gaps could generate waves and the modulation of those waves with voice?

I can somewhat understand how the spark-gap was devised to transmit waves and how the waves were first measured in frequency but what lead to the idea of "modulation" where another electrical signal ...
Sedumjoy's user avatar
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How did people in pre-Ampere period deduce this?

How did people before Ampere (eg-Coulomb) who used magnetic-pole model, know that only two surfaces (north and south poles) of a bar magnet exerts and experiences force while the rest of the surfaces ...
lorilori's user avatar
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Why are capacitors and inductors called that way?

I do understand that electrical resistance describes somehow the material resistance to electrons flow but I don't see the meaning behind the names capacitors and inductors (if there is any and it ...
Learn_and_Share's user avatar
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Who was the first to invent the induction motor?

I have heard that Galileo Ferraris and Nikola Tesla invented the induction motor independently. Does anyone know who was the first and were they similar in power output and design? This may be a ...
user5039's user avatar
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Why do so many electronic equipment work on the same or close frequencies?

I know for example that one of the reasons why our cellular phones need to be turned off in airplanes is that the navigation system of the plane (GPS and other systems) works on frequencies close to ...
user2554's user avatar
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