Cant understand Gaussian surface

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SUMMARY

Gaussian surfaces are hypothetical closed surfaces used in conjunction with Gauss' Law, a fundamental principle in electromagnetism, to relate the electric flux through the surface to the total charge enclosed. The choice of Gaussian surface, such as spherical, cylindrical, or cubic, is determined by the symmetry of the charge distribution, allowing for simplified calculations of the electric field. By selecting a surface that aligns with the symmetry of the problem, one can derive the electric field more easily, making Gaussian surfaces a powerful tool in electrostatics.

PREREQUISITES
  • Understanding of Gauss' Law and its application in electromagnetism
  • Familiarity with electric flux and charge distributions
  • Knowledge of basic geometry, particularly spheres, cylinders, and cubes
  • Concept of symmetry in physical systems
NEXT STEPS
  • Study the derivation and applications of Gauss' Law in various charge configurations
  • Explore examples of electric field calculations using spherical Gaussian surfaces
  • Investigate the role of symmetry in simplifying electromagnetic problems
  • Learn about other Maxwell Equations and their interrelations with Gauss' Law
USEFUL FOR

Students of physics, particularly those studying electromagnetism, educators explaining electric field concepts, and anyone seeking to understand the practical applications of Gaussian surfaces in solving electrostatic problems.

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Homework Statement


Can someone please explain what use gaussian surfaces have, in really simple terms?
I don't really understnd the point of wrapping an imaginary surface around a charge, when we can just do the calcs without the imaginary surface.
Also if there are preset gaussian surfaces that are commonly used (sphere, cube, cylinder) how do we know which surface to use? and also wouldn't perfect shapes (gaussian) be intrincially and largely inaccurate, and if so, then again what is the point of superimposing an imaginary surface over the real thing?


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The Attempt at a Solution

 
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A gaussian surface is a hypothetical [closed-]surface that encloses some volume of interest.

When used with Gauss' Law [one of the Maxwell Equations], it relates the outward electric-flux through that surface with the total charge enclosed within that surface. This relationship is independent of the choice of gaussian surface so long as the same charges are enclosed.

If the surface is [chosen] sufficiently "nice" so that the total electrix-flux \oint \vec E\cdot d\vec A can be expressed more simply, one may be able to go further and solve explicitly for the electric-field everywhere on that gaussian surface. That's why problems with spherical [respectively, cylindrical] symmetry suggest using a spherical [respectively, cylindrical] gaussian surface. Some problems are more easily solved by exploiting the symmetries of the problem with Gauss' Law.
 
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basically we use a gaussian surface to make it easier to solve for E. For example integral(E.da) = |E|*(surface area of gaussian surfce) then we relate this to the total charge enclosed or the density at points within a volume. The symmetry of the surface chosen allows us to say E=|E|
 

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