The problem:(adsbygoogle = window.adsbygoogle || []).push({});

An infinitely long rod of radius R carries a uniform volume charge

density ρ (ρ > 0).

(a) Show how to use Gauss' Law to prove that the

electric field inside this rod points radially

outward and has magnitude:

[itex] E = \rho r/2\epsilon_0[/itex]

(b) Integrate the electric field over an appropriate

displacement to find the potential difference from

the rod's surface to its axis. State explicitly

which of those two locations is at the higher

potential.

My answer:

I solved for part (a) using a Gaussian surface symmetry and got this as my final answer.

[itex] E(2 \pi rL) = \rho r/2 \epsilon_0[/itex]

[itex] E = \rho r/2\epsilon_0[/itex]

I am having a hard time starting part (b). I am not sure where to start.

**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: Infinitely long rod

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