Understanding Gauss's Law: Electric Flux & Charge Enclosed by a Closed Surface"

In summary, Gauss's law states that the electric flux through a closed surface is equal to the total charge enclosed by the surface divided by the electric constant. This applies to situations where there are charges both inside and outside the surface, with the electric field being due to all the charges. However, only the total charge inside the surface is represented by the term "q" in Gauss's law. The net flux through the surface from all charges not enclosed by the Gaussian surface is 0, as the flux into the interior of the space also exits through another part of the surface. The net flux through the surface is therefore only from the enclosed charge.
  • #1
gracy
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Electric flux through a closed surface S
= q/ε0
(1.31)
q = total charge enclosed by S
In the situation when the surface is so chosen that there are some charges inside and some outside, the electric field [whose flux appears on the left side of Equation above is due to all the charges, both inside and outside S. The term q on the right side of Gauss’s law, however, represents only the total charge inside S.I want to know how that's work?
 
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  • #2
The flux from all charges not enclosed by the gaussian surface = 0. This is because the flux through the surface into the interior of the space enclosed by the Gaussian surface also passes through another part of the surface upon exiting the space so the net flux into the space = 0. Net flux through the surface is from enclosed charge only.

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1. What is Gauss's Law?

Gauss's Law is a fundamental law in electromagnetism that relates the distribution of electric charges to the resulting electric field. It states that the electric flux through a closed surface is equal to the net charge enclosed by that surface divided by the permittivity of free space.

2. How is Gauss's Law used in practical applications?

Gauss's Law is used to calculate the electric field in situations with high degrees of symmetry, such as a charged spherical shell or a long, straight wire. It is also used in the design and analysis of electrical circuits and devices.

3. What is electric flux?

Electric flux is a measure of the amount of electric field passing through a given area. It is defined as the dot product of the electric field and the area vector, and is typically measured in units of volts per meter squared (V/m2).

4. Can Gauss's Law be applied to any closed surface?

Yes, Gauss's Law can be applied to any closed surface, as long as the electric field is constant and perpendicular to the surface at every point. This is known as the "normal" condition. If the electric field is not constant or not perpendicular to the surface, more complex mathematical methods must be used to calculate the electric flux.

5. How is charge enclosed by a closed surface calculated?

The charge enclosed by a closed surface can be calculated by adding up the charges within the surface, taking into account the sign of each charge. In cases where the charge is distributed continuously, such as a uniformly charged sphere, the charge can be calculated by integrating the charge density over the volume enclosed by the surface.

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