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!

Why does the E-field inside a cylinder =0?

  1. Jan 28, 2013 #1
    1. The problem statement, all variables and given/known data

    Figure 24-32 shows a section of a long, thin-walled metal tube of radius R, carrying a charge per unit length  on its surface. Derive expressions for E in terms of distance R from the tube axis, considering both (a) r > R and (b) r < R. Plot your results for the r = 0 to r = 5cm, assuming that  λ= 2*10^-8
    C=m//and R = 3cm


    [i cant put the figure since the question is in the book]

    2. Relevant equations

    q = ε0 ∫ E dA

    3. The attempt at a solution

    i got the answer to (a) E=λ/2∏rε0

    i dont understand why (b) is 0
     
  2. jcsd
  3. Jan 28, 2013 #2
    urgent help due tomorrow
     
  4. Jan 28, 2013 #3

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You know that field inside a closed conductor, with no internal charges, is 0. You can think of this as being because field lines cannot pass through it. This tube is 'long'; as long as you are not near the ends, any field reaching in from outside will be small.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Why does the E-field inside a cylinder =0?
  1. Why is the e field 0? (Replies: 5)

Loading...