(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Consider a finite wire which lies on the z-axis and extends from the point z=-Λ to the point z=+Λ. The vector potential in the xy plane a distance s from the wire is:

Λ->∞

A=(µₒI/2π) ln (2Λ/s) k̂

An equally good vector potential is given by A'=A+∆λ, where λ is any scalar field we wish to choose. Determine a suitable choice for λ which has the property that A' remains finite in the limit Λ->∞.

(Let ∆ be rotated 180 to be the gradient.)

2. Relevant equations

I found the curl of A=(µₒI/2π) ln (2Λ/s) k̂ to find the magnetic field, and I got:

A*= -(µₒI/2πs)

3. The attempt at a solution

Ok, here is what I did:

I figured that I had to find a value of λ that gave way to a A' that when you took the curl of it would yield A*. At first, I just tried to find a value of λ that was involving ln (...)k̂,

but then I saw that A' would then depend (s), and it would be tricky to find a value. Then I saw the hint that it was better if λ didn't depend on (s).

So, if I just want A, can I just choose a random constant for λ? Like 4 or something?

Please Help!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: E/M Vector Potential of finite Wire

**Physics Forums | Science Articles, Homework Help, Discussion**