Force on Moving Charges Concept

Demonstrations in Force on Moving Charges

Hand holding a magnet against a color CRT monitor screen, producing dramatic swirling rainbow distortion of the test pattern image
Safety

CRT Monitor in Magnetic Field

A strong magnet visibly distorts the image on a color CRT monitor by deflecting the electron beams via the Lorentz force. Students observe the cross-product relationship between field direction, electron …
Complete setup: Xantrex power supply (4.35 V, 0.5 A) connected to a wooden induction coil box, which drives a Crookes tube on a wooden stand showing a straight green electron beam; red-and-black bar magnet rests on the table below
Safety

Electron Beam Tube

A visible electron beam in a Crookes tube deflects when a bar magnet is brought near, directly demonstrating. Approaching from different directions shows the cross-product geometry and confirms the sign …
e/m apparatus: large Helmholtz coils on a stand with e/m tube (wrapped in dark shielding) at center, multiple power supplies and meters on a wooden table in a lecture hall
Safety

e/m Experiment

Electrons accelerated through a known potential are deflected into circular paths by Helmholtz coils, enabling direct measurement of. Demonstrates the Lorentz force on moving charges and connects to Thomson's discovery …
Safety

Cyclotron Model

Mechanical analog of a cyclotron: an oscillating plate tilts at the "cyclotron frequency" while ball bearings spiral outward through a groove, demonstrating that orbital period is independent of particle velocity. …