Editing Lorentz force (section)

== Physical interpretation of the Lorentz force ==

[[Coulomb's law]] is only valid for point charges at rest. In fact, the electromagnetic force between two point charges depends not only on the distance but also on the [[relative velocity]]. For small relative velocities and very small accelerations, instead of the Coulomb force, the [[Weber electrodynamics|Weber force]] can be applied. The sum of the Weber forces of all charge carriers in a closed DC loop on a single test charge produces – regardless of the shape of the current loop – the Lorentz force.

The interpretation of magnetism by means of a modified Coulomb law was first proposed by [[Carl Friedrich Gauss]]. In 1835, Gauss assumed that each segment of a DC loop contains an equal number of negative and positive point charges that move at different speeds.<ref>{{cite book | last = Gauss | first = Carl Friedrich | title = Carl Friedrich Gauss Werke |volume=5 | publisher = [[Göttingen Academy of Sciences and Humanities|Königliche Gesellschaft der Wissenschaften zu Göttingen]] | year = 1867 | page = 617}}</ref> If Coulomb's law were completely correct, no force should act between any two short segments of such current loops. However, around 1825, [[André-Marie Ampère]] demonstrated experimentally that this is not the case. Ampère also formulated a [[Ampère's force law|force law]]. Based on this law, Gauss concluded that the electromagnetic force between two point charges depends not only on the distance but also on the relative velocity.

The Weber force is a [[central force]] and complies with [[Newton's laws of motion|Newton's third law]]. This demonstrates not only the [[Momentum|conservation of momentum]] but also that the [[conservation of energy]] and the [[Angular momentum|conservation of angular momentum]] apply. Weber electrodynamics is only a [[quasistatic approximation]], i.e. it should not be used for higher velocities and accelerations. However, the Weber force illustrates that the Lorentz force can be traced back to central forces between numerous point-like charge carriers.