Questions tagged [electromagnetism]

Electromagnetism is a branch of Physics involving the study of the electromagnetic force, a physical interaction that occurs between electrically charged particles. This force plays a major role in determining the internal properties of most objects encountered in daily life. Originally, electricity and magnetism were considered to be two separate forces. This view changed with the publication of James Clerk Maxwell's treatise on electricity and magnetism.

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Why is one of Maxwell's equations named after Ampère? Who first named it after Ampère?

Ampère never wrote down what is confusingly called "Ampère's circuital law," not even the form without the displacement current term, as Ampère never dealt with the field concept.* Maxwell derived $$\...
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Who discovered the magnetic vector potential, $\vec{A}$?

Neither Maxwell’s fundamental differential equations on electromagnetism nor Einstein’s first papers considered the magnetic vector potential A. So who discovered, formulated or used A for the first ...
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Electromagnetic constants and the speed of light

Was it known before Maxwell's time that the vacuum permitivity was inversely related to the permeability by a factor of $c^2$?
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Who originally derived the general force law equation of force between current elements?

Wikipedia credits this to Maxwell. This derivation can be found in Maxwell's Treatise on Electricity and Magnetism vol. 2, part 4, ch. 2 (§§502-527). I went through the derivation and found two self ...
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Why is Maxwell and not Ampère credited for unifying electricity and magnetism?

Ampère, a half century before Maxwell, theorized that magnetism was caused by electrical currents. So, why is Maxwell and not Ampère credited for unifying electricity and magnetism? (cf. the question ...
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How did scientists plot complicated graphs in the 19th century?

I am wondering how did Maxwell in the 19th century draw such figures as the one shown? What tools or procedures did he need? Is it all compass and ruler drawing?
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How did gyromagnetic ratio come up before quantum mechanics, and who introduced it?

I am really curious about who was the first one to define the gyromagnetic ratio $\gamma$ of a body, i.e. the ratio of its magnetic dipole momento to its angular momentum. It is a very important ...
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Were there serious attempts to model the photoelectric effect classically?

Today we see the photoelectric effect as one of the simplest pieces of empirical evidence that leads to quantum physics. The historical development of the subject, however, seems to have involved much ...
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How did Maxwell conclude that light is an electromagnetic wave?

This is a copy of a question I just asked at Physics Stack Exchange. From reading the text on the related questions, it seems that Maxwell equated light with the carrier of electromagnetic force just ...
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Where in Gauss's works does he derive "Gauss's Law"?

Where in Gauss's works does he derive "Gauss's Law"? Or is "Gauss's Law" named after Gauss for a different reason?
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Several questions about Gauss's contributions to electromagnetism

First of all, i appologize if i'm asking too many questions about Gauss (and some will also say "not very interesting questions"); i know i might appear ridiculus - but i really think it's an ...
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What did Einstein learn in his university electricity and magnetism courses?

What did Einstein learn in his university electricity and magnetism courses? Did he learn about such prominent results as Ampère's force law, Weber's force law derived from it (cf. Maxwell's Treatise §...
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Was it suspected that the speed of electricity was equal to the speed of light?

Was it believed early on that signals sent via wire moved at exactly the speed of light or simply very fast? Who was the first to estimate the speed? EDIT: Given that they move at less than the ...
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Why do Maxwell's equations bear his name?

Maxwell's equations in their modern differential form are: $\nabla \cdot \mathbf{E} = \dfrac {\rho} {\varepsilon_0}$ (Gauss's law for electricity) $\nabla \cdot \mathbf{B} = 0$ (Gauss's law for ...