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Fluorescent and Neon Tubes in an Electric Field

A fluorescent tube swings at the end of a long plexiglass rod. It is made to rotate and then brought near the Van de Graaff generator. The tube lights up when there is a potential difference between its ends. This happens when it is pointing radially away from the Van de Graaff. The same can be done with a small neon tube.

Comments (3)

Hi, Can any one explain how the energy is conserved in this case?? Where does the neon, tube gets the energy?? I mean its an electric field but there is no current flow from the generator in this case and the circuit is open in the case of the tubes..

Posted 4 years by subramaniann

The possibility that I could think of is that the electrons/Ions in the tube is aligning itself due to electric field and in turn causes the tube to glow.. but in this case at one point it should stop glowing once the capacitor is fully charged… and since the tube is rotating it should continuously glow as the capacitor gets constantly charged and discharged/or charged in reverse direction

Posted 4 years by subramaniann

There should be a force acting on the tubes too due to electrostatic repulsion and attraction on the electrons and ions!!!

Posted 4 years by subramaniann

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MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated almost 2 years ago

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March 16, 2010 13:44
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