## Phase Shift and The Jumping Ring

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##### Date

2023-02-08

##### Authors

Luke, Ella

Bronkhorst-Ilavsky, Simon

Rantz, Lucas

Littmann, Nika

##### Keyword

physics

##### Abstract

This experiment centered around and developed the model of the Thomson Jumping Ring. The purpose
of this experiment was to move past the weak Lenz’s Law justification and provide another explanation
for the jumping phenomena: the phase shift between driving and induced currents. By measuring the
driving and induced currents for a range of frequencies, the phase shift was determined. The phase shift
was compared to induced current and it was shown that induced current is directly proportional to sin
of the phase shift, demonstrating that induced current increases at higher phase shifts. Larger induced
currents lead to stronger force interactions with the solenoid’s magnetic field, which shows that the
magnitude of the force acting on the ring is related to phase shift. The jump height of the ring and
observations of its behaviour when it was allowed to levitate proved that the direction of the force
acting on the ring is also importantly proportional to phase shift. At small phase shifts, the force acting
on the ring oscillates between pushing it up and pulling it down, and as phase shift increases the force
proportionately spends more time per oscillation pushing up. At very high frequencies, the force acts
entirely to push the ring upwards. These two dependencies on phase shift, one for the magnitude of
force and one for direction of the force, show that Lenz’s Law is not enough to describe the Thompson
Jumping Ring phenomena, and that an analysis of the ring and solenoid current phase shift is required.