Point charge and electric flux

AI Thread Summary
The discussion revolves around calculating the electric flux through a sphere centered at a distance x from a point charge, with a radius less than x. Participants express confusion over the concept that since the sphere does not enclose the charge, the enclosed charge (q_enc) would be zero, suggesting that the electric flux should also be zero. However, it is pointed out that the net electric field lines entering and exiting the Gaussian surface result in a non-zero flux, despite the sphere not containing the charge. Clarification is sought regarding the correct answer, as there seems to be a conceptual misunderstanding about the relationship between electric field lines and flux. The conversation highlights the importance of understanding electric field behavior in relation to Gaussian surfaces.
channel1
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Homework Statement


You measure an electric field E at a distance x from a point charge. What is the electric flux through a sphere whose center is at that distance and whose radius is less than x from the charge?


Homework Equations


E*dA = (q_enc)/(e_0)


The Attempt at a Solution


I'm not sure that I'm understanding the question...The sphere does not enclose the point charge since its center is at x and its radius is less than x from the charge, so doesn't that mean q_enc = 0 and the flux is 0? (I have the answer so I know it's not zero, but I don't understand what I'm missing conceptually here...)
 
Physics news on Phys.org
net flux is 0
it means the new electric field lines crossing the total surface is 0
look at pic ... all field lines entering exit the Gaussian surface ! so net field through surface is 0
 

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channel1 said:

The Attempt at a Solution


I'm not sure that I'm understanding the question...The sphere does not enclose the point charge since its center is at x and its radius is less than x from the charge, so doesn't that mean q_enc = 0 and the flux is 0?
I believe that is correct.
(I have the answer so I know it's not zero, but I don't understand what I'm missing conceptually here...)
That's weird, what is the "correct" answer that you have been given?
 
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