Van De Graaf Generator & Gauss's Law

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SUMMARY

The Van de Graaff generator operates on principles outlined by Gauss's law, demonstrating that no charge exists on the inner surface of its conducting shell. Despite the presence of a charged belt, which transfers charge to the outer surface, the system maintains electrostatic conditions, as there is no current flowing within the generator. The generator continues to accumulate charge until a potential difference causes coronal discharges or breakdown of air. This mechanism exemplifies Gauss's law, confirming that the charges are distributed only on the outer surface of the shell.

PREREQUISITES
  • Understanding of Gauss's Law
  • Familiarity with electrostatics
  • Knowledge of Van de Graaff generator operation
  • Basic principles of electric fields
NEXT STEPS
  • Study the derivation of Gauss's Law and its applications in electrostatics
  • Explore the mechanics of Van de Graaff generators in particle acceleration
  • Investigate the effects of potential difference and breakdown voltage in air
  • Learn about the relationship between static electricity and charge distribution
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Physics students, electrical engineers, educators, and anyone interested in the principles of electrostatics and the operation of Van de Graaff generators.

matangi7
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My Textbook states"The same principle behind Faraday’s ice pail experiment is used in a Van de Graaff electrostatic generator (Fig. 22.26). A charged belt continuously carries charge to the inside of a conducting shell. By Gauss’s law, there can never be any charge on the inner surface of this shell, so the charge is immediately carried away to the outside surface of the shell."
How is Gauss's law relevant to the Van De Graaf Generator? Doesn't the situation have to be electrostatic to apply Gauss's law? Doesn't a Van De Graaf Machine have a current flowing, not static charges? Attached is the diagram in my textbook.
618670-22-10DQEI1.png
 

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The machine that is shown will continue to carry charges to the dome until such time as the accumulated charge will create a potential difference with the surrounding air as to cause coronal discharges or full breakdown of the air with a discharge to ground.reducing the net charge on the sphere. When used as a charged particle accelerator the dome is connected to its base by a string of very high resistance resistors to bleed off charge along with the particle beam while the charge deposited on the belt is carefully regulated to maintain the desired potential on the dome.
 
The Van de Graff generator is actually a demonstration of Gauss law. The fact that no charge is present inside the surface of the shell ( in this case, it is the inner surface of the shell) is one of the results of gauss law. Here's a link to the derivation of how no charge exists inside a shell: https://ucscphysicsdemo.wordpress.c...lectric-field-inside-and-outside-of-a-sphere/
And gauss law can be applied to moving charges too, but also then, in the case of the van de graff generator, the charges are only transferred via the charged belt and distributed on the outer surface of the shell and cannot really be called "moving charges". Also, there is no "current " flowing, its just static electricity.
 

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