Ampere-meter: Difference between revisions

Browse history interactively

← Previous edit

Content deleted Content added

VisualWikitext

Inline

Latest revision as of 12:12, 11 June 2017

Redirect to:

Ammeter

@@ Line 1: / Line 1: @@
+#REDIRECT [[Ammeter]]
-[[Image:Ampere-o-meter-vintage-HDR-0h.jpg|thumb|A vintage ampere meter.]]
-The '''ampere-metre''' which has the symbol '''A m''', '''A-m''',  or '''A·m''' is the [[SI]] unit for [[magnetic pole|pole]] strength in a [[magnet]].
+{{Redirect category shell|1=
-==Derivation==
+{{R from related topic}}
-[[Einstein]] proved that a [[magnetic field]] is the [[theory of relativity|relativistic]] part of an [[electric field]]. This means that while an electric field acts between [[electric charge|charges]], a magnetic field acts between ''moving'' charges (as a charge moves through space more quickly and through time more slowly, its [[electromagnetism|electromagnetic force]] becomes more magnetic and less electric). Therefore, the pole strength is the product of charge and [[velocity]].
+{{R to article without mention}}
+}}
-<math>1~\mathrm{A \cdot m} = 1~\mathrm{C} \cdot \frac{\mathrm{m}}{\mathrm{s}}</math>
-==Usefulness==
-Few calculations actually involve the strength of a pole in ampere-metres because a [[monopole|single magnetic pole]] has never been isolated.  Magnets are [[dipole|dipoles]] which require more complicated calculations than monopoles.  However, the strength of a magnetic field is measured in [[Tesla_(unit)|teslas]] and one tesla is one [[Newton_(unit)|newton]] per ampere-metre which confirms that the unit for pole strength is indeed the ampere-metre.
-==Misconceptions==
-Charge is usually thought of as a [[scalar]] or a [[quantum number]] while velocity is a [[Vector (spatial)|vector]].  In fact, charge is a vector whose direction is determined by the [[Spin (physics)|spin]] of a particle, but [[macroscopic]] calculations are not concerned with this direction and define charge to be along an [[Cartesian Coordinate System|axis]] so that the direction of another vector is really its direction relative to charge. A vector pointing along an axis becomes one-dimensional, or identical to a scalar.
-The idea that magnetic forces act on moving charges is clear in an [[electromagnet]] but not obvious in a [[permanent magnet]]. In fact, all substances have charges moving in them all of the time, one of the difficulties in reaching [[absolute zero]]. In most substances, all of the magnetic fields produced by this motion cancel each other out, but magnetic substances have more proper alignment. At the microscopic level, many molecules are magnets — [[hydrogen fluoride]] for example is a dipole. [[Polarity]] is most often expressed in terms of [[electronegativity]] but the strength of its poles could be expressed in ampere-metres as well.
-==References==
-*[http://www.phys.unsw.edu.au/einsteinlight/jw/module2_FEB.htm| the electric and magnetic forces between moving charges]
-*[http://www.qsl.net/g4cnn/units/units.htm| units in electricity and magnetism]
-[[Category: SI derived units]]