Understanding the Equation B = del x A in Electromagnetic Theory

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In summary, the conversation is about a homework problem involving finding an error in a proof using the equations of curl and divergence. The equations used are B = \nablax A from electromagnetic theory and Gauss's Law for magnetic fields. The person is unsure of the physical interpretation of the equation and is asking for clarification. A is described as the vector potential of B, but it is unclear if it has any physical meaning or if it is simply a necessary vector. Additional resources are provided for better understanding.
  • #1
lalligagger
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Homework Statement



Not going to write out the whole problem (yet). It's a "find the error in the incorrect proof" type of question in a section on curl and divergence.

Homework Equations



B = [tex]\nabla[/tex]x A is given as an equation of "electromagnetic theory" and used in the proof. It's stated that the error is not in this equation. The other equation used in the proof is Gauss's Law for magnetic fields, but I get that one.

The Attempt at a Solution



Haven't really tried; I'd like to know the physical interpretation of the above equation before I start staring at integrals. I just got through electricity and magnetism in my general physics course, but this doesn't look familiar. I'm assuming that A is some type of force field, but what field would satisfy the equation?
 
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  • #2
Well μH = ∇ X A

Magnetic Force
 
  • #3
Thanks Pion, but can you elaborate? What is μH and how does it relate to B?
BTW, this is for a course that basically covers vector calculus that our math department doesn't in early calc classes. The question is really just about applying Stoke's theorem, which I understand pretty well. It's just the one equation that I don't get is keeping me from even starting the problem.
I can try and scan the problem if more context is needed, but it's nothing I want to write out here.
 
  • #4
Ok, A is the vector potential of B. Does A have any physical meaning or is it just an arbitrary vector that must exist because [tex]\nabla[/tex][tex]\bullet[/tex]B=0?
 

FAQ: Understanding the Equation B = del x A in Electromagnetic Theory

What is the meaning of B = del x A?

The equation B = del x A represents the curl of vector A. This means that it calculates the amount of rotation or angular momentum of a vector field at a given point.

How is del x A different from regular multiplication?

Del x A is not a traditional multiplication operation, but rather a vector calculus operation. It involves taking the partial derivatives of vector components and performing a cross product to find the resulting vector.

What is the physical significance of B = del x A?

The physical significance of B = del x A is that it represents the amount of rotational or swirling motion present in a vector field. This can be useful in various fields such as fluid dynamics, electromagnetism, and astronomy.

Can B = del x A be applied to any vector field?

Yes, B = del x A can be applied to any vector field, as long as the field is defined in three-dimensional space and is differentiable.

How is B = del x A used in real-world applications?

B = del x A is used in various real-world applications, such as calculating the magnetic field in electromagnetism, determining the vorticity in fluid dynamics, and analyzing the movement of celestial bodies in astronomy.

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