Editing Lorentz force (section)

=== Formulation in the Gaussian system ===
The above-mentioned formulae use the conventions for the definition of the electric and magnetic field used with the [[SI]], which is the most common. However, other conventions with the same physics (i.e. forces on e.g. an electron) are possible and used. In the conventions used with the older [[Gaussian units|CGS-Gaussian units]], which are somewhat more common among some theoretical physicists as well as condensed matter experimentalists, one has instead
<math display="block">\mathbf{F} = q_\mathrm{G} \left(\mathbf{E}_\mathrm{G} + \frac{\mathbf{v}}{c} \times \mathbf{B}_\mathrm{G}\right),</math>
where {{mvar|c}} is the [[speed of light]]. Although this equation looks slightly different, it is equivalent, since one has the following relations:<ref group="nb" name="units" />
<math display="block">q_\mathrm{G} = \frac{q_\mathrm{SI}}{\sqrt{4\pi \varepsilon_0}},\quad
\mathbf E_\mathrm{G} = \sqrt{4\pi\varepsilon_0}\,\mathbf E_\mathrm{SI},\quad
\mathbf B_\mathrm{G} = {\sqrt{4\pi /\mu_0}}\,{\mathbf B_\mathrm{SI}}, \quad
c = \frac{1}{\sqrt{\varepsilon_0 \mu_0}}.</math>
where {{math|''ε''<sub>0</sub>}} is the [[vacuum permittivity]] and {{math|''μ''<sub>0</sub>}} the [[vacuum permeability]]. In practice, the subscripts "G" and "SI" are omitted, and the used convention (and unit)  must be determined from context.