A teaching tape for SR-12, charge and current density

charge and current transformation

Teaching tape demonstrating the transformation of charge and current density under a 0.6c boost.

Open SR-12 with these settings

Where it starts

The settings the tape begins from, under the constant set modern-si-2019. Values are the model's own, not the laboratory control's display: a radius of 5e-7 is half a micrometre.
SettingValue
Observer boost speed (boost)179875474.8
Charge density (stationary frame) (chargeDensity)0
Current density Jx (currentDensityX)1

What it changes, and what to expect

  1. Set Observer boost speed (boost) to 179875474.8 describes the same world from somewhere else

    charge-current-0.6c

    At 0.6c a neutral wire with Jx=1 A/m² develops a net charge density rho'=-2.5017e-9 C/m³ while current transforms to J'x=1.25 A/m².

These are the values the tape's author recorded, not a result this page computed. Nothing here runs the instrument. Open SR-12 with these settings: the link opens it with them already in place. Compare what it gives you with what is recorded here. The settings travel in the link and the laboratory reads them as it loads, so without JavaScript it opens at its worked example instead.

Every teaching tape