How Does a Rotating Metallic Bar Generate a Potential Difference?

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Discussion Overview

The discussion revolves around the phenomenon of a rotating metallic bar and its ability to generate a potential difference. Participants explore the underlying mechanics and factors influencing this potential difference, including the role of centrifugal force and the properties of the bar.

Discussion Character

  • Exploratory
  • Technical explanation

Main Points Raised

  • One participant, DaTario, proposes that as a metallic bar rotates, centrifugal force may cause electrons to displace more than protons, potentially leading to a potential difference.
  • DaTario inquires about the necessary information to calculate this potential difference, listing factors such as length, mass, volumetric density, resistance, and angular velocity.
  • Another participant suggests reviewing Richard Tolman's 1916 experiment as a relevant reference for understanding the phenomenon.
  • There is clarification regarding the abbreviation "ddp," which stands for potential difference in Portuguese.

Areas of Agreement / Disagreement

The discussion does not appear to reach a consensus, as participants express different levels of understanding and reference historical experiments without resolving the main question about the potential difference generated by the rotating bar.

Contextual Notes

Participants have not fully defined the assumptions regarding the behavior of electrons and protons in the rotating bar, nor have they detailed the mathematical framework needed for the calculations mentioned.

DaTario
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rotating metalic bar and potential difference

Hi All,

I have been thinking of this lately and had no answer.

Consider we have a metalic bar rotating around one of its ends. Centrifugal force will appear inside the bar. It seems natural to think that electrons will suffer larger displacements than protons. Thus a potential difference seems to arise. If all this is correct, what do we need (complementary information, for instance) in order to calculate the potential difference from:

the length L
the mass
the volumetric density
the resistance
the angular velocity.

?

Best wishes

DaTario
 
Last edited:
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i don't know what you mean with ddp.

Despite i suggest that you take a look at the experiment which Richard Tolman conducted in 1916. That would have led you in the right direction.
 


saunderson said:
i don't know what you mean with ddp.

Sorry, I used a portuguese shortage for potential difference (Diferença De Potencial). I have it corrected now in the OP.

Thank you ( I will search for this reference Tolman).

Best Wishes

DaTario
 
Last edited:
saunderson said:
Despite i suggest that you take a look at the experiment which Richard Tolman conducted in 1916. That would have led you in the right direction.

Thank you.

Nice reference.

Best Wishes


DaTario
 

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