Author(s)

Antonio Šunjerga^1,2, Franjo Sokolić², Marcos Rubinstein³, Farhad Rachidi¹

¹Electromagnetic Compatibility Laboratory, EPFL, Switzerland.
²Department of Physics, Faculty of Science, Split, Croatia.
³University of Applied Sciences Western Switzerland, Yverdon-les-Bains, Switzerland.

It is commonly assumed that a wire conducting an electric current is neutral in the laboratory frame of reference (the rest frame of the lattice of positive ions). Some authors consider that the wire is neutral only in a symmetrical frame of reference, in which the velocities of electrons and protons have equal norm and opposite direction. In this paper, we discuss the Lorentz transformation between different frames of reference in the context of the special theory of relativity for a current-carrying conducting wire and a probe charge in motion with respect to the wire. A simple derivation of the Lorentz force in the laboratory frame of reference for the assumed neutrality in a symmetrical frame of reference is presented. We show that the Lorentz force calculated assuming neutrality in the symmetrical frame of reference and the one assuming neutrality in the laboratory frame of reference differ by a term corresponding to a change in the test charge speed of one half the drift velocity of the electrons.

Special Theory of Relativity, Current-Carrying Wire, Neutral Frame, Symmetrical Frame, Lorentz Force, Drift Velocity

Šunjerga, A. , Sokolić, F. , Rubinstein, M. and Rachidi, F. (2018) Lorentz Force from a Current-Carrying Wire on a Charge in Motion under the Assumption of Neutrality in the Symmetrical Frame of Reference. Journal of Modern Physics, 9, 2473-2481. doi: 10.4236/jmp.2018.914159.