Where the electric field is zero

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Homework Help Overview

The problem involves two fixed charges, -20.6 microC and +4.2 microC, separated by a distance of 3.3 m, and seeks to determine where the net electric field is zero along the line connecting the charges. Additionally, it asks for the force on a third charge, +24.1 microC, placed at that location.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to find the location where the electric field is zero and has calculated a distance from the positive charge. However, they express uncertainty about how to approach the second part of the problem involving the force on the third charge.
  • Some participants suggest calculating the force between the third charge and the positive charge, noting that the force due to the other charge would be equal and opposite.
  • There is a question raised about the meaning of "equal and opposite" in the context of the forces acting on the third charge.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem. Some guidance has been offered regarding the calculation of forces, but there is still uncertainty about the implications of the forces being equal and opposite.

Contextual Notes

Participants are navigating the complexities of a three-charge system and the implications of electric fields and forces in such a setup. There may be assumptions about the arrangement and interactions of the charges that are yet to be fully clarified.

JJones_86
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Homework Statement


Two charges, -20.6 microC and +4.2 microC, are fixed in place and separated by 3.3 m.

(a) At what spot along a line through the charges is the net electric field zero? Locate this spot relative to the position of the positive charge.

(b) What would be the magnitude of the force on a third charge +24.1 microC placed at this spot?


Homework Equations



F = k (q1*q2)/r^2

The Attempt at a Solution



None

-----------------

I've got part A to be 2.71679m from the positive charge, I just don't know how to do part B. The equation I posted seems to me irrelevant because there are now 3 charges. Any help is appreciated.
 
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(b) What would be the magnitude of the force on a third charge +24.1 microC placed at this spot?
Find the force between +24.1 microC and+ 4.2 micro C. Force due to other charge will be equal and opposite to this force.
 
rl.bhat said:
(b) What would be the magnitude of the force on a third charge +24.1 microC placed at this spot?
Find the force between +24.1 microC and+ 4.2 micro C. Force due to other charge will be equal and opposite to this force.

F = k*q1*q2/r^2
F = 8.99E9(4.2E-6)(24.1E-6)/2.71679^2
F = 0.123286 N?
 
rl.bhat said:
(b) What would be the magnitude of the force on a third charge +24.1 microC placed at this spot?
Find the force between +24.1 microC and+ 4.2 micro C. Force due to other charge will be equal and opposite to this force.

I'm not exactly sure what you mean by equal and opposite, would it make it 0 N then?
 

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