How to find a hollow cuboid's resistance

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Discussion Overview

The discussion focuses on determining the electrical resistance of a hollow cuboid between two points on the same face, specifically when the points are not located on the edges. The context includes considerations of uniform resistivity and the potential effects of deformation on resistance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about finding a formula for resistance between two points on a hollow cuboid, noting that the line joining the points is parallel to the length of the cuboid.
  • Another participant suggests that a simple formula may not exist due to the non-uniform distribution of the electric field and current, indicating that numerical methods might be necessary to solve the relevant differential equations.
  • There is a repeated question regarding whether the resistance would change if the cuboid is deformed, with one participant clarifying the difference between "crumbled" and "crumpled" and providing differing answers based on the interpretation of these terms.
  • A different viewpoint proposes conducting an experiment to measure resistance, suggesting that practical experimentation could yield qualitative insights using common materials like aluminum foil and a multimeter.

Areas of Agreement / Disagreement

Participants express differing views on the effects of deformation on resistance, with some asserting that crumpling does not change resistance while others suggest that crumbling does. The discussion remains unresolved regarding the existence of a simple formula for resistance.

Contextual Notes

The discussion highlights the complexity of the theoretical treatment of resistance in hollow cuboids, with limitations noted in the applicability of simple formulas and the need for empirical approaches.

hackhard
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how to find a hollow cuboid's resistance between two points on same face but not lying on the edges. the line joining 2 points is parallel to the length of the cuboid.
resistivity is uniform
another related doubt - will resistance between those same points change if the cuboid is deformed (the box is crumbled)
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If you are looking for a simple formula I am afraid you won't find it. The distribution of electric field and current is not uniform. And they depend on each other.
You probably need numerical methods to solve the differential equations.
Maybe some empirical formula may be found, if such is used in some industrial application.
 
hackhard said:
will resistance between those same points change if the cuboid is deformed (the box is crumbled)
 
hackhard said:
will resistance between those same points change if the cuboid is deformed (the box is crumbled)
"Crumbled" means broken into pieces, as when a cookie is broken into crumbs. Answer: Yes
"Crumpled" means deformed or its shape changed without breaking off any pieces. Answer: No. If surfaces don't touch each other and the material is not stretched.
 
I'm not so sure about this. As the theoretical treatment is very complicated, I suggest to simply to an experiment, measuring the resistance. I guess it's not so difficult to do qualitatively with house-hold means. Just use aluminum foil and wrap a cubic box (easily tinkered with some cardboard. Also nearly any modern digital multimeter has an ohm-meter mode :-).
 

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