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: Finding potential difference between two points on a cone

  1. Dec 27, 2009 #1
    Hello

    I am solving some problems from "Intro to EM" by David Griffiths ( third edition)
    Problem 2.26 ( attached file 2.26.jpg) and I have also attached the solution from the solution
    manual (griffiths-2.26.jpg). For both part a and b I am getting different answer.

    I have chosen vertex as the origin and the axis of the cone as the positive z-axis.
    The bottom of the cone is toward positive z axis. Now any differential area element on the cone would be (using cylindrical coordinates) , x*d(phi)*dz , where x is the perpendicular
    distance of the area element from the z-axis. But for this geometry, x=z for any point on the
    cone , so dz = dx. The distance r of this area element from the origin(vertex) would be
    sqrt(2)*x. I am supposed to use the formula (formula.jpg).

    Why are my solutions not working ? Or is the instructor's solution manual incorrect ?

    Regards
    I Newton
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Dec 27, 2009 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hello issacnewton! :smile:

    I can see the instructor's solution but not your solution. :confused:
     
  4. Dec 27, 2009 #3
    hello tiny-tim

    i will write my solution though i just explained what i did. i see people here write using LateX. how can i write like that ? is there any 'How to' tutorial for doing that ?

    Newton
     
  5. Dec 28, 2009 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hello issacnewton! :smile:

    (just got up :zzz: …)

    LaTeX is very easy.

    The best way to see how to use it is click the "QUOTE" button on someone else's post and copy what they do. :wink:

    There's a list of symbols and a guide at http://www.physics.udel.edu/~dubois/lshort2e/node61.html#SECTION008100000000000000000" [Broken]

    and there's also a palette of symbols if you click the ∑ tag just above the Reply box (though I never use it).
     
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook