5K30.30 Light Bulb with AC Field in Coil

PURPOSE: To further demonstrate Faraday's Law.

DESCRIPTION: A large coil can be energized with AC, placed under the lecture table, and a bulb-and-coil combination on top of the table can be lit wirelessly when it moves into the AC field of the hidden coil.

SETUP TIME: Medium to high

COMPONENT LIST:

    


  1.  Coil 1055						???


  2.  Coil 5259 + No. 90   OR  Coil 1547 + No. 1204.	???


  3.  Bulb						From Light Source Area

SUGGESTIONS: A good demo of B = uH can be achieved with Leybold 1000-turn + No. 303; Burns much brighter when Leybold core is inserted.

REFERENCES: 2122 4.78, 9.2; PIRA 5K30.30

OTHER NOTES: Another way to do this: A large, open-frame transformer has been adapted for demonstration purposes. The secondary has been removed, leaving only the primary. When a few turns of wire are wrapped around the primary, forming a make-shift secondary, a lamp can be lighted. Or a heavy piece of copper bar stock can be bent around the primary; sparks can be drawn and heating effects observed from this one-turn secondary (I measured the current in one case at 160 amperes!). For more advanced students, mention can be made of the closure of line integrals and the indifference of the emf to the path length.