Does Gauss's Law hold true for a point charge near a sphere?

In summary, a point charge is placed on the x-axis at x=4 and a sphere with radius 3cm is placed beside it at the origin. The electric field from the point charge is found to be greater at the near end (x=3) compared to the far end (x=-3). This suggests that calculating the inward and outward flux would result in a non-zero net, which raises the question of whether this violates Gauss's Law. However, upon further examination and considering the intuition behind the situation, it is found that Gauss's Law still applies in this case. The density of the electric field lines indicates the strength of the field and also the flux through a surface, leading to the conclusion that the number of arrows entering
  • #1
ehabmozart
213
0
Consider a point charge on the x-axis at x=4. And a sphere with radius 3cm is kept beside the point charge centered at the origin. Consider the near end (x=3) and the far end (x=-3) ... We will find that E from the point charge is much bigger in the close end than E at the far end. So if we calculate inward and outward flux to get the net, this would not be zero since they strike the same area. Does this vilate with Gauss's Law??
 
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  • #2
When in doubt, do the math. You will (hopefully) find that Gauss's law also applies in this case.
 
  • #3
The intuition behind this case is as follows:

We think of the electric field as a bunch of arrows (field lines), with the density of them telling you the strength of the field. But they also tell you the flux through a surface, the more arrows, the more flux. If you think about the situation you came up with, how many arrows enter the sphere, and how many leave? (if you have a hard time thinking about this, "follow" a single arrow from the point charge, towards the sphere, and out to infinity. What does it do?) Does this violate gauss' law?
 

1. What is Gauss's Law?

Gauss's Law is a fundamental law in physics that describes the relationship between electric fields and electric charges. It states that the electric flux through a closed surface is proportional to the total enclosed charge.

2. How is Gauss's Law used in science?

Gauss's Law is used to calculate the electric field in situations where there is symmetry in the distribution of charges. It is also commonly used in the study of electromagnetism and electrostatics.

3. What is the mathematical formula for Gauss's Law?

The mathematical formula for Gauss's Law is ∮E•dA = q/ε0, where ∮E•dA is the electric flux through a closed surface, q is the total enclosed charge, and ε0 is the permittivity of free space.

4. What is the significance of Gauss's Law?

Gauss's Law is significant because it provides a useful tool for calculating electric fields in scenarios with symmetry, which would otherwise be mathematically complex. It also helps to explain the behavior of electric charges and their interactions with electric fields.

5. What are some real-world applications of Gauss's Law?

Gauss's Law has many practical applications, such as in the design of electrical circuits, the study of lightning and thunderstorms, and the development of technologies like particle accelerators and capacitors. It also plays a crucial role in understanding the behavior of electric fields in everyday objects and systems.

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