Electric field outside a gaussian surface

In summary, Gauss's law states that the electric field at a gaussian surface is only related to the enclosed charge, not outer charges.
  • #1
Ibraheem
51
2
Hello

If we have a gaussian surface that is placed in a uniform electric field E and encloses 0 charge, what would the E-field at the gaussian surface be? I have assumed the gaussian surface to be cubic surface, and then I have found from Gauss's law that the electric field is zero at the surface even though there is a constant electric field. Can someone please clarify what I am not getting here. Is the electric field in the closed surface integral of Gauss's law is only related to the enclosed charge or is related to outer charges.

Thanks
 
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  • #2
It is only related to the enclosed charge. Think about it this way. The field lines from unenclosed charge that enter the Gaussian surface will exit it eventually, producing no net flux.
 
  • #3
So gauss's law provides information related to the enclosed charge, but nothing about electric field and charge magnitude outside the gaussian surface.
 

Related to Electric field outside a gaussian surface

1. What is a gaussian surface?

A gaussian surface is an imaginary surface that is used to simplify calculations of the electric field in a given region. It is chosen such that the electric field is perpendicular to the surface at all points.

2. How is the electric field outside a gaussian surface calculated?

The electric field outside a gaussian surface can be calculated using Gauss's Law, which states that the flux of the electric field through a closed surface is equal to the total charge enclosed by that surface divided by the permittivity of free space.

3. How does the electric field outside a gaussian surface differ from the electric field inside?

Inside a gaussian surface, the electric field is constant and uniform, while outside the gaussian surface, the electric field varies depending on the distribution of charges. Additionally, the electric field outside the gaussian surface is always perpendicular to the surface, while inside it can have different directions.

4. Can a gaussian surface be any shape?

No, a gaussian surface must have certain properties in order for Gauss's Law to be applicable. It must be a closed surface, and the electric field must be perpendicular to the surface at all points. A common example of a gaussian surface is a sphere, but other shapes can also be used.

5. Why is the electric field outside a gaussian surface important?

The electric field outside a gaussian surface is important because it helps us understand the behavior of electric charges in a given region. By using Gauss's Law, we can calculate the electric field at any point outside the gaussian surface and use this information to analyze and predict the behavior of electric charges in that region.

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