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relates the integrated magnetic field around a closed loop to the electric current passing through the loop
In classical electromagnetism, Ampère's circuital law, often simply called Ampère's law, and sometimes Oersted's law, relates the circulation of a magnetic field around a closed loop to the electric current passing through … Wikipedia
Factsheet
Named after André-Marie Ampère
Named after André-Marie Ampère
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Wikipedia
en.wikipedia.org › wiki › Ampère's_circuital_law
Ampère's circuital law - Wikipedia
April 30, 2026 - In classical electromagnetism, Ampère's circuital law, often simply called Ampère's law, and sometimes Oersted's law, relates the circulation of a magnetic field around a closed loop to the electric current passing through that loop. The law was inspired by Hans Christian Ørsted's 1820 discovery ...
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HyperPhysics
hyperphysics.phy-astr.gsu.edu › hbase › magnetic › amplaw.html
Ampere's Law
The magnetic field in space around an electric current is proportional to the electric current which serves as its source, just as the electric field in space is proportional to the charge which serves as its source. Ampere's Law states that for any closed loop path, the sum of the length elements ...
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Physics LibreTexts
phys.libretexts.org › bookshelves › university physics › introductory physics - building models to describe our world (martin et al.) › 22: source of magnetic field
22.3: Ampere’s Law - Physics LibreTexts
March 28, 2024 - This is different from Gauss’ Law, where the integral is over a closed surface (not a closed path, as it is here). In the context of Gauss’ Law, we refer to “calculating the flux of the electric field through a closed surface”; in the context of Ampere’s Law, we refer to “calculating the circulation of the magnetic field along a closed path”.
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Open Yale Courses
oyc.yale.edu › physics › phys-201 › lecture-10
PHYS 201 - Lecture 10 - Ampere's Law | Open Yale Courses
Ampere's Law is used to find the magnetic field generated by currents in highly symmetric geometries like the infinitely long wire and the solenoid. It is shown how magnetism can be used to convert macroscopic mechanical energy to do microscopic electrical work.
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YouTube
youtube.com › the organic chemistry tutor
Ampere's Law & Magnetic Field of a Solenoid - Physics & Electromagnetism - YouTube
This physics video tutorial provides a basic introduction into ampere's law and explains how to use ampere's law to derive the formula to calculate the magne...
Published   December 19, 2017
Views   90K
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Reddit
reddit.com › r/askphysics › can anyone explain the main premise of ampere’s law to me?
r/AskPhysics on Reddit: Can anyone explain the main premise of Ampere’s Law to me?
December 9, 2020 -

I’m just lost, I can’t understand this law at all, what’s the main point of the law? Why are we calculating the B at evry point and adding it up? What does that give us? Also what does elemental length mean

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amperes law has two forms, the 'differential' one which is the curl of the magnetic field, and the usual one you use, called the 'integral' one. ill focus on the integral form. the integral form is obtained from the differential form by applying stokes theorem to a closed curve. so, the reason why you calculate B at every point and add it up is kind of from theorems from vector calculus. amperes law is the magnetic form of gauss's law. just like we could integrate pieces of charge dq to find the electric field at a point, we can integrate dl x r (cross product that you usually convert to just dl) according to the biot savart law to find the magnetic field at a point. these are the brute force methods. with the electric field, we found the shortcut, gauss's law, to find the electric field at a point. when we had enough symmetry, we were able to choose a nice surface, calculate the flux through it where E is constant, set it equal to 4pi q, and solve for the magnitude of E there. amperes law is our same shortcut with the magnetic field. when we have enough symmetry, we draw an imaginary loop of wire where B is constant in magnitude over, find its line integral over this, and set it equal to 4pi I/c and solve for B. any problem we do with amperes law, we could do with the biot savart law (though it will take longer to do). while we can technically do every problem we do with biot savarts law with amperes law, not all problems are symmetric enough to let us easily use amperes law. by elemental length, i think you mean the line element. which is a tiny vector at some point on the loop pointing to the next tiny vector on the loop
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Why are we calculating the B at evry point and adding it up? Because that quantity, the integral of B around a closed path, turns out to have the same value no matter what path you take, and depends only on the current flowing through the closed path. Physicists just love it when they find something that's "always the same no matter what". For instance, think about conservation of energy, conservation of momentum, the constant speed of light, etc. Often it makes calculations much simpler, and often it leads to profound insights about the nature of the universe. In this case, both are true. Often you can use Ampere's Law to find an unknown magnetic field, and when it works it's usually a much simpler calculation than using the Biot-Savart law.
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Study.com
study.com › science courses › physics: high school
Ampere's Law | Definition, Equation & Examples - Video | Study.com
April 14, 2015 - Ampere's Law states that the magnetic field created by an electric current is proportional to that current's size.
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Encyclopedia Britannica
britannica.com › science › physics › matter & energy
Ampère’s law | Electricity, Magnetism, Physics | Britannica
June 15, 2026 - Ampère’s law, one of the basic relations between electricity and magnetism, stating quantitatively the relation of a magnetic field to the electric current or changing electric field that produces it.
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Albert.io
albert.io › home › ampere’s law: ap® physics c e&m review
Ampere's Law: AP® Physics C E&M Review | Albert Blog & Resources
April 2, 2026 - Ampère’s Law is the magnetic counterpart of Gauss’s Law for electricity: instead of a closed surface integral, it uses a closed line integral, and instead of relating the integral to enclosed charge, it relates the integral to enclosed current. Choosing the right closed path (the “Ampèrian loop”) transforms a potentially difficult integral into a one-step multiplication.
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OpenStax
openstax.org › books › university-physics-volume-2 › pages › 12-5-amperes-law
12.5 Ampère’s Law - University Physics Volume 2 | OpenStax
October 6, 2016 - This result is similar to how Gauss’s law for electrical charges behaves inside a uniform charge distribution, except that Gauss’s law for electrical charges has a uniform volume distribution of charge, whereas Ampère’s law here has a uniform area of current distribution.
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Brilliant
brilliant.org › wiki › amperes-law-quantitative
Ampere's Law | Brilliant Math & Science Wiki
One of Maxwell's equations, Ampère's law, relates the curl of the magnetic field to the current density and is particularly useful for current distributions with high degrees of symmetry.
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Ximera
ximera.osu.edu › em › electromagnetics › magnetostatics › digInAmpereLaw
Ampere’s Law - Ximera
Ampere’s law for static magnetic fields states that the magnetic field’s integral around closed contour is equal to the current enclosed by the contour.
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YouTube
youtube.com › flipping physics
Ampère's Law
🧲 Welcome back to Flipping Physics! Today, let's unravel the mysteries of Ampère’s law, the magnetic field counterpart to Gauss’ law in electricity. Ampère’...
Published   March 12, 2024
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URI Digital Commons
digitalcommons.uri.edu › cgi › viewcontent.cgi pdf
15. Ampere's law for the magnetic field with applications
The figures below illustrate Gauss’s laws for the electric and magnetic fields in the context of an electric ... The circulation integral of the magnetic field ⃗B around any closed curve (loop) C is equal to the net electric ... Note: Only the component of ⃗B tangential to the loop contributes to the integral. The positive current direction through the loop is determined by the right-hand rule. ... The line integrals H ⃗B · d⃗s along the three Amperian loops are as indicated.
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TeachEngineering
teachengineering.org › lessons › view › van_mri_lesson_7
Ampere's Law - Lesson - Teach Engineering
July 20, 2017 - Use Ampere's law to calculate the magnetic field around a current loop.
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Open Source Physics
compadre.org › physlets › electromagnetism › intro28.cfm
Physlet Physics: Chapter 28: Ampere's Law
As with Gauss's law, to use Ampere's law we depend on the symmetry of the configuration to make the needed simplifications to the calculations. Once we have expressions for fields from current carrying wires, we can investigate interactions between wires.