Proof that e-field lines don't cross

In summary, the reason electric field lines do not cross is because it violates existence-uniqueness and the concept of equipotential surfaces. Additionally, the dynamical systems and non-linear dynamics play a role in explaining this phenomenon. The lines are drawn perpendicular to the equipotential surfaces and if they were to cross, it would create a contradiction in the direction of the electric field at a single point. This is due to the fact that the electric field can only have one value at a given point in time.
  • #1
vortmax
19
1
I understand that electric field lines do not cross and a simple explanation is that it violates existence-uniqueness. I'm thinking there is a more complete explanation out there though. I think the answer lies in the realm of dynamical systems and non-linear dynamics, but it's been a whlie since I've had that and can't piece together the theorems that would fully explain it.
 
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  • #2
I'm not sure if this is the right answer, but classically, when analyzing electric fields, you take the vector sum...so technically, if field lines did cross, then you'd have a vector sum there; thus, altogether, you have a "unique" direction at each point.
 
  • #3
vortmax said:
I understand that electric field lines do not cross and a simple explanation is that it violates existence-uniqueness. I'm thinking there is a more complete explanation out there though. I think the answer lies in the realm of dynamical systems and non-linear dynamics, but it's been a whlie since I've had that and can't piece together the theorems that would fully explain it.

Easy. "Field lines" are just arbitrary lines drawn in a direction that is always perpendicular to every possible equipotential surface that they pass through. If the lines ever crossed, what would the equipotential surface look like at the point where they cross? A surface can only have one normal (subject to scalar multiplication), not two, so it can't have two lines coming out in different directions at the same place that are both perpendicular to it!
 
  • #4
They simply can't cross because E can't have two values at a single time. Consider this, an electron can either push away a proton near it or the proton can push the electron, these two events cannot occur at the same time. Similarly, E can't have two values and hence electric field lines can't cross each other.
 

1. What are e-field lines?

E-field lines are lines that represent the direction and strength of the electric field surrounding a charged object. They are used to visualize the electric field and its properties.

2. Why is it important that e-field lines don't cross?

The fact that e-field lines do not cross is a fundamental property of electric fields. It helps us understand the direction and magnitude of the electric field at any point in space. If e-field lines were allowed to cross, it would imply that the electric field has multiple directions and magnitudes at a single point, which goes against our understanding of electric fields.

3. How can we prove that e-field lines don't cross?

We can prove that e-field lines do not cross by conducting experiments and using mathematical equations. For example, we can use a charged object and a test charge to map out the electric field lines. Additionally, the mathematical equation for electric field lines, given by Coulomb's Law, also shows that the lines cannot cross.

4. Are there any exceptions to the rule that e-field lines don't cross?

In most cases, e-field lines do not cross. However, there are some exceptions, such as in the presence of multiple charges. In this case, the e-field lines from different charges may overlap or interact with each other, but they still do not physically cross.

5. What are the implications of e-field lines not crossing?

The fact that e-field lines do not cross allows us to accurately predict and understand the behavior of electric fields. It also helps us in practical applications, such as designing electrical circuits and devices, as we can use the direction and strength of the e-field lines to determine the flow of electricity.

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