5H30.10 - E - Beam Deflection - Cathode Ray Tubes

Code Number:
5H30.10
Demo Title:
E - Beam Deflection - Cathode Ray Tubes
Condition:
Good
Principle:
Interaction of Electric and Magnetic Fields
Area of Study:
Electricity & Magnetism
Equipment:
Cathode Tube, Solid-State Induction Coil Power Supply, 6 Volt DC Power Supply, Old Open Frame Oscilloscope, Magnets, and Demo Cathode Tubes.
Procedure:

Hook the electron tube to the induction coil.  Turn on the coil and make sure the polarity is set correctly.  Bring a magnet to the back side of the tube and observe the deflection.  Use the other pole of the magnet and again observe the deflection.  Place the electron tube under the wire instead of the compass.  Turn on the current and observe the deflection.  Change the direction of the current flow in the wire and again observe the deflection.

Bring a magnet to the tube of the old oscilloscope and observe the deflection whether bringing a magnet in from the side or the front.

CAUTION: Since the oscilloscope case is open the electronics are exposed.  Be careful when using the magnet.

The old electron tubes are for demonstration purposes to show construction.

References:
  • T. Toepker, M. Fatuzzo, and A. Prentice, "Addendum to 'Charged Particle Dynamics in the Magnetic Field of a Long Straight Current Carrying Wire'", TPT, Vol. 53, #5, May 2015, p. 262.
  • A. Prentice, M. Fatuzzo, and T. Toepker, "Charged Particle Dynamics in the Magnetic Field of a Long Straight Current-Carrying Wire", TPT, Vol. 53, #1, Jan. 2015, p. 34.
  • Kent W. Scheller and Thomas J. Pickett, "F = qv × B: v is with Respect to What?", TPT, Vol. 51, #3, Mar. 2013, p. 169. 
  • Craig F. Bohren, "Can an Electron Rotate a Brick?", TPT, Vol. 47, #1, Jan. 2009, p. 9.
  • Mario Capitolo and William Lonc, "Magnetic Deflection Demonstrator", TPT, Vol. 38, #5, May 2000, p. 277.
  • Paul Hewitt, "Figuring Physics", Vol. 35, #1, Jan. 1997, p. 55.
  • Lawrence A. Ferrari and Kenneth E. Jesse, "Experiment to Measure e/m for an Electron", TPT, Vol. 34, #7, Oct. 1996, p. 434.
  • J. G. Shepherd, "Magnetic Experiments with a Cathode Ray Tube", TPT, Vol. 5, #4, Apr. 1967, p. 153.
  • F. E. Christensen, "The Oscilloscope and How It May Be Used", TPT, Vol. 1, #4, Oct. 1963, p. 172.
  • J. Fukai, G. D. Thaxton, and E. T. Kinzer, "Crookes's Tube Electron Beam Deflection by Hand", AJP, Vol. 51, #6, June 1983, p. 572.
  • "B-015. Oscilloscope Beam-Discharge Tube", DICK and RAE Physics Demo Notebook, 1993.
  • G. D. Freier and F. J. Anderson, "Ep-11", A Demonstration Handbook for Physics.
  • G. D. Freier and F. J. Anderson, "Ep-8", A Demonstration Handbook for Physics.
  • Robert J. Reiland, Laboratory Activity 8: "Magnetic Forces on Moving Charged Particles", Teaching About Magnetism, p. 3.31.
  • David Kutliroff, "84. The Unshielded Cathode Ray Tube", 101 Classroom Demonstrations and Experiment For Teaching Physics, p. 186.
  • Julien Clinton Sprott, "5.1. Magnet and Cathode Ray Tube", Physics Demonstrations, ISBN 0-299-21580-6, p. 210.
  • Robert Ehrlich, "M.5. Deflection of an Electron Beam", Turning the World Inside Out and 174 Other Simple Physics Demonstrations, p. 161.
  • "The Cathode Ray Oscilloscope", Selective Experiments in Physics, CENCO, 1962.
  • Curt Suplee, "Magnetism and Our Lives", Everyday Science Explained, National Geographic, p. 84 - 85.
  • W. Bolton, "50. The Cathode Ray Oscilloscope", Book 4 - Electricity, Physics Experiments and Projects, 1968, p. 97 - 98.




Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.