Urgent: Understanding Vector Potential from a Straight Wire

In summary, the conversation discussed finding the vector potential at a distance s from an infinite straight wire carrying current I. The answer was determined to be A=A(s) z in cylindrical coordinates, with A(s)=(mu*I/2*pi)ln(s/a)z when a is a constant. The question was then raised about why the vector potential points in the same direction as the current. It was explained that for an infinite straight wire, the direction of the current density J is fixed, resulting in A pointing in the same direction as I.
  • #1
fredrick08
376
0
urgent EMM question

Homework Statement


find the vector potential a distance s from an infinite straight wire carrying current I, check that dell dot A=0 and dellxA=B...

ok i know the answer is A=A(s) z, in cylindricals. A(s)=(mu*I/2*pi)ln(s/a)z when a is a constant.

can someone please explain to me why A points in the same direction as I?

please, i need this asap, because i have no idea.
 
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  • #2


[tex]\vec{A}=\frac{\mu_{0}}{4\pi}\int_{V}\frac{\vec{J}}{|\vec{r}-\vec{r}\:'|}d^{3}r' [/tex]

For an infinite straight wire, the direction of the current density J is fixed. Therefore ...
 
  • #3


Thankyou! = )
 

1. What is vector potential?

Vector potential is a mathematical concept used in electromagnetism to describe the magnetic field of a given system. It is a vector quantity and is closely related to the magnetic vector potential.

2. How is vector potential related to a straight wire?

In the context of a straight wire, the vector potential describes the magnetic field that is produced by a steady current flowing through the wire. It can be calculated using the Biot-Savart Law.

3. Why is understanding vector potential from a straight wire important?

Understanding vector potential from a straight wire is important because it allows us to accurately predict and analyze the magnetic field around the wire. This is crucial in many practical applications, such as designing electronic devices and studying electromagnetic phenomena.

4. Can vector potential be measured directly?

No, vector potential cannot be measured directly. It is a mathematical construct that helps us understand and calculate the magnetic field. However, the effects of vector potential can be observed and measured through the magnetic field it produces.

5. Are there any real-world examples of vector potential from a straight wire?

Yes, there are many real-world examples of vector potential from a straight wire. Some common examples include power lines, electric motors, and antennas. In all of these cases, the vector potential plays a crucial role in determining the behavior of the magnetic field around the wire.

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