I am trying to figure out how it would effect the ressistance R of a wire with length L and variyng cross-sectional area A(x) if the current density was a fuction of the radius of the wire. That is J = J(r).(adsbygoogle = window.adsbygoogle || []).push({});

I'm having trouble with this when it seems like ressistance is the result of a derivation of ohm's law assuming constant E-field such that [tex]E = \frac{J}{\sigma} = \frac{V}{l}[/tex], but if E is not constant how can one then relate the ressitance to the current-density J?

A qualitative answer is good enough.

**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: Ressistance when current-density is not constant

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