Net flux through a closed sphere

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SUMMARY

The net electrical flux through a closed sphere of radius R in a uniform electric field is definitively zero, as there is no charge enclosed within the sphere. This conclusion can be mathematically demonstrated using the first half of Gauss's Law, specifically by integrating the flux over area elements of a hemisphere aligned with the electric field. The integration of these area elements confirms that the total flux through the closed surface is zero, consistent with the principles of electrostatics.

PREREQUISITES
  • Understanding of Gauss's Law in electrostatics
  • Familiarity with single-variable calculus
  • Knowledge of electric fields and flux concepts
  • Ability to perform surface integrals
NEXT STEPS
  • Study Gauss's Law and its applications in electrostatics
  • Learn about surface integrals and their role in calculating flux
  • Explore electric field concepts in uniform fields
  • Investigate the mathematical proofs related to flux through various geometries
USEFUL FOR

Students of physics, particularly those studying electromagnetism, educators teaching electrostatics, and anyone interested in understanding the mathematical foundations of electric flux in closed surfaces.

PeteyCoco
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Find the net electrical flux through a closed sphere of radius R in a uniform electric field

I know that the flux is going to be 0 since there is no charge enclosed, but how would I show this mathematically? The next half of the question asks about a cylinder with sides parallel to the electric field, which I can prove is 0 easily, but I'm not sure if I know the math to prove the first scenario. Can the sphere-problem be proven with only knowledge of Single-Variable calc?

EDIT: I guess I'm asking if this can be proven easily using the first half of Gauss's Law, ignoring (Q-internal)/(epsilon-nought)
 
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Yes, it can be done with a single-variable integral.

You can visualize that the sphere has an "axis" aligned with the electric field. For area elements, take rings that are centered on that axis, something like this:
images?q=tbn:ANd9GcScKzbiYeomeocc55pBJpWhmYUKtXiqEEj4w3nIbxwtelBZndR1.png
Integrate the flux over all the area elements in a hemisphere, and you'll get that hemisphere's contribution to the total flux.

Hope that's clear enough.
 

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