What is the excess charge on the surface of the earth?

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Homework Help Overview

The problem involves calculating the excess charge on the surface of the Earth based on the vertical electric field at its surface, which is given as 117 N/C. The context includes concepts related to electric fields and charge distribution.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to use the equation relating electric field and charge but encounters difficulties with their calculation. Another participant suggests using the formula for electric flux as an alternative approach.

Discussion Status

Participants are exploring different methods to approach the problem, with one providing a suggestion for an alternative formula. There is acknowledgment of the permittivity constant, which may play a role in the calculations discussed.

Contextual Notes

There is a mention of the radius of the Earth being a necessary parameter for the calculations, but specific values or additional context regarding the setup are not provided.

gallib
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Homework Statement



The Earth has a vertical electric field at the surface, pointing down, that averages 117 N/C. This field is maintained by various atmospheric processes, including lightning. What is the excess charge on the surface of the earth?


Homework Equations



E=ke*Q/r^2 Q=Er^2/ke

The Attempt at a Solution



I attempted to plug in E = 117, r= radius of the earch, and ke= 8.99*10^9 into the equation to find Q, but this answer was wrong. Any ideas, thanks.
 
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Why don't you use the formula for Electric flux? The Net electric flux through surface is basically Electric field * (4pi*(radius of Earth ^ 2)) = excess charge / permittivity constant.
 
Ah..thank you.
 
Last edited:
Yeah, permittivity constant is 8.85*10^-12.
 

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