Electric Force/ charge problem; missing electrons

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SUMMARY

The discussion centers on calculating the number of missing electrons from a pith ball experiencing an electrostatic force of 4.5 x 10^-3 N towards another pith ball with a net charge of 2.3 nC, located 22 mm away. Using Coulomb's Law (F = kqq/r^2), the user derived the charge of the first pith ball as 1.05 x 10^-7 C. Dividing this charge by the elementary charge (1.6 x 10^-19 C) results in approximately 6.58 x 10^11 missing electrons. The user correctly notes that this should represent a repulsive force, indicating a discrepancy in the charge distribution.

PREREQUISITES
  • Coulomb's Law (F = kqq/r^2)
  • Understanding of electric charge and elementary charge (e = 1.6 x 10^-19 C)
  • Basic algebra for manipulating equations
  • Concept of electrostatic forces and their directionality
NEXT STEPS
  • Study the implications of charge conservation in electrostatics
  • Learn about the concept of electric field strength and its calculation
  • Explore the principles of electrostatic forces in different configurations
  • Investigate the effects of charge imbalance on physical objects
USEFUL FOR

Students in physics, particularly those studying electrostatics, as well as educators and anyone interested in understanding the calculations related to electric forces and charge interactions.

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Homework Statement



How many electrons are missing from a pith ball which feels an electrostatic force of
4.5 x 10^-3 N torward a second pith ball 22 mm away with a net charge of 2.3 nC.

Homework Equations



q= ne; charge of an object equals the number of electrons x the charge of an electron

F= kqq/r^2


The Attempt at a Solution



F= kqq/r^2
q=(Fr^2)/kq

q=((4.5 x 10^-3 N)(0.022 m)^2)/((8.99 x 10^9)(2.3 x 10^-9))

q=1.05 × 10^-7
q=ne

(1.05 x 10^-7)/(1.6 x 10^-19)= 658,000,000,000= 6.58 x 10^11 electrons ? Is that right?
 
Last edited:
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It looks good except it should be a repulsive force, if electrons are missing.

Plugging the unknown charge back in gives the Force OK.
 

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