Find Earth's charge using Gauss's Law

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SUMMARY

The total charge on Earth's surface, calculated using Gauss's Law, is approximately -735.56 kC based on an electric field measurement of 163 N/C. The formula applied was Q = EAɛo, where E is the electric field, A is the surface area of Earth, and ɛo is the permittivity of free space (8.85 x 10^-12 F/m). The calculation utilized Earth's radius of approximately 6.4 x 10^6 m, resulting in a surface area of about 41 x 10^12 m². Despite the calculations, the result was deemed incorrect, indicating a need for further verification of the accuracy of the constants and methodology used.

PREREQUISITES
  • Understanding of Gauss's Law and its application in electrostatics
  • Familiarity with electric field concepts and measurements
  • Knowledge of the permittivity of free space (ɛo)
  • Basic skills in algebra and geometry for surface area calculations
NEXT STEPS
  • Review the derivation and application of Gauss's Law in electrostatics
  • Investigate the significance of the permittivity of free space (ɛo) in calculations
  • Learn about the implications of electric field measurements on charge distribution
  • Explore common sources of error in electrostatic calculations and how to mitigate them
USEFUL FOR

Students studying electromagnetism, physics educators, and anyone interested in understanding the application of Gauss's Law to real-world scenarios involving electric fields and charge distributions.

ndoc
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Homework Statement



The electric field just above the surface of Earth has been measured to typically be 163 N/C pointing downward.

What is the total charge on Earth's surface implied by this measurement?

Homework Equations



∫EdA = Qinside/ɛo


The Attempt at a Solution



I solved this two ways and got the same answer, which is apparently wrong. using Gauss's Law: EA = Q/ɛo => Q=EAɛo = (-163)(4*pi*r^2)ɛo = -735.56 kC
 
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ndoc said:

Homework Statement



The electric field just above the surface of Earth has been measured to typically be 163 N/C pointing downward.

What is the total charge on Earth's surface implied by this measurement?

Homework Equations



∫EdA = Qinside/ɛo


The Attempt at a Solution



I solved this two ways and got the same answer, which is apparently wrong. using Gauss's Law: EA = Q/ɛo => Q=EAɛo = (-163)(4*pi*r^2)ɛo = -735.56 kC

Earth's radius is about 6.4E6 m so squared is about 41E12 m^2.
 
right so these are my numbers:

4*pi*(-163)*(8.85x10^-12)*(6.37x10^6)^2

but this produces a wrong answer (has to be within about 97% accuracy) of -735562.52C
or -735.56 kC
 

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