1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Resistance of a holow sphere

  1. Sep 21, 2009 #1
    1. The problem statement, all variables and given/known data
    Determine a formula for the total resistance of a spherical shell made of material whose conductivity is [tex]\sigma[/tex] and whose inner and outer radii are r1 and r2. Assume the current flows radially outward.

    2. Relevant equations
    [tex]\sigma[/tex] = 1/[tex]\rho[/tex]

    R = ([tex]\rho[/tex]*l)/A

    3. The attempt at a solutionSince the current is moving outward, l (length) is going to be the difference of the radii. How do I account for the changing surface area?

    The solution is (r1 - r2)/(4[tex]\pi[/tex]*[tex]\sigma[/tex]*r1*r2)

    EDIT: *facepalm* I spelled hollow wrong...
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted