Confused about this force calulation in Resnick Halliday Krane Electrostatics

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Discussion Overview

The discussion revolves around a calculation in electrostatics from the Resnick Halliday Krane textbook, specifically regarding the force exerted by charges when the distance is halved. Participants express confusion about how the changes in charge and distance affect the Coulombic force.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions how the charge changing by a factor of 1/8 leads to the Coulombic force also becoming 1/8, suggesting that the reduction in distance should also be considered.
  • Another participant agrees that while the charge ratio is correctly calculated, the distance ratio has been overlooked in the textbook's explanation.
  • Some participants express frustration with the textbook's accuracy and their own understanding of the concepts in electromagnetism.

Areas of Agreement / Disagreement

Participants generally agree that the textbook's calculation is flawed due to neglecting the distance factor, but there is no consensus on the implications of this oversight or how it affects their understanding of the concepts.

Contextual Notes

Participants express uncertainty about their grasp of the material and the correctness of the textbook, indicating a need for further clarification on the principles involved.

KnightTheConqueror
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TL;DR
Resnick Halliday Krane Electrostatics Sample Problem 25-7 doubt
I'm confused in the calculation for R/2. The author took in account that the charge will change by a factor 1/8. But how does it show that the coloumbic force will become 1/8th. The distance will also reduce by half shouldn't that also be taken into account? Or am I missing something here?
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KnightTheConqueror said:
TL;DR Summary: Resnick Halliday Krane Electrostatics Sample Problem 25-7 doubt

I'm confused in the calculation for R/2. The author took in account that the charge will change by a factor 1/8. But how does it show that the coloumbic force will become 1/8th. The distance will also reduce by half shouldn't that also be taken into account? Or am I missing something here?View attachment 336703
Been there, done that. You are correct and the book is wrong. See discussion here.
https://www.physicsforums.com/threa...rted-on-an-electron-inside-a-nucleus.1052346/
 
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I agree with you - they've correctly calculated the charge ratio and forgotten the distance ratio.

Edit: beaten to it, I see.
 
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:welcome:
 
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KnightTheConqueror said:
Thank you, i just started electromagnetism and i got disappointed that perhaps I'm not getting proper grasp of the concepts. Thanks for clarifying the book is wrong
I wish you success with your studies. If you need more help, you know where to find it.
 

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