Reexamination of Barnett's Experiment Based on the Modified Lorentz Force Law

Abstract

Barnett's experiment demonstrates that the induction on a stationary cylindrical capacitor in the presence of a rotating magnet or solenoid is zero. In this investigation, based on the modified Lorentz force law, which complies with Galilean transformations and depends on relative velocities, the induction on the capacitor is reexamined. When the rotating solenoid is long and the capacitor is placed inside the solenoid, it is seen that the induction actually vanishes as observed in Barnett's experiment. However, when the capacitor is placed outside the solenoid or when the solenoid is short, it is shown that the induction can departure from zero. This prediction provides a means to test the validity of the modified Lorentz force law.