5H30.20 - e/m - Electromagnetic Deflection of Electron Beam - Small

Code Number:
Demo Title:
e/m - Electromagnetic Deflection of Electron Beam - Small
Measure e/m of Electrons
Area of Study:
Electricity & Magnetism
Electron beam deflection tube, 12 V DC power supply, 5 kV DC power supply (2), Helmholtz coils, old black and white or color TV, horseshoe magnets or large neodymium magnets.

Assemble the apparatus as shown and according to the diagrams enclosed. Trying this before class for practice is a very good idea.  The small apparatus which will show only a 90 degree bend at best because of the small diameter of the Helmholtz coils.

  • Michel Glascock, M. Sparlin, "Thomson's e/m Experiment Revisited", AJP, Vol. 40, # 11, Nov. 1972, p. 6631.
  • Ei-18:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • W. Bolton, "The Action of Electric and Magnetic Fields on a Beam of Electrons", Book 4 - Electricity, Physics Experiments and Projects, 1968, p. 45-47.

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