Potential energy in concentric shells

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The discussion revolves around calculating the potential energy of an outer neutral shell due to an inner charged shell. It is established that the potential at the outer shell due to the inner shell is KQ/b, but since the outer shell has no charge, its potential energy is zero. Participants clarify that the electric field remains unchanged with the outer shell in place, and thus no energy is required to position it. The conversation also touches on the complexities introduced by the thickness of the outer shell and the concept of induced charges, emphasizing the need to reassess potential energy calculations in such scenarios. Overall, the consensus is that the outer shell's potential energy remains zero due to its neutral charge.
  • #61
gracy said:
The answer I got is indeed a correct answer.
Your work looks correct.
 
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  • #62
ehild said:
The question was "A solid conducting sphere of radius a having a charge Q is surrounded by a conducting shell of inner radius 2a and outer radius 3a as shown.Find the amount of heat produced when switch is closed."
Where is that switch?
The switch makes a connection from the solid sphere to the shell.
 
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  • #63
SammyS said:
The switch makes a connection from the solid sphere to the shell.
Have you seen that switch anywhere in the thread, or you could see the original figure in Gracy's book due to your supernatural abilities?
 
  • #64
ehild said:
Have you seen that switch anywhere in the thread, or you could see the original figure in Gracy's book due to your supernatural abilities?
Had to be the latter.:smile:
 
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  • #65
ehild said:
Have you seen that switch anywhere in the thread, or you could see the original figure in Gracy's book due to your supernatural abilities?
Not supernatural. (Thanks for the vote of confidence, TSny).

Back in Post #47, I suggested to gracy, that she edit the OP. In that suggestion, I added a few words to her restated problem as it appeared in Post #4.

I knew about the switch from a link to a video that gracy sent to me in a pm.

I should have pushed harder for her to give a more complete statement of the problem.
Here is a screen shot:
upload_2016-1-17_15-30-51.png


Here is the figure at a larger scale.
upload_2016-1-17_15-46-52.png


This video can be found on the site: physicsgalaxy.com , by Ashish Arora.
 
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