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!

Potential in case of concentric shells program

  1. Nov 11, 2015 #1
    1. The problem statement, all variables and given/known data
    Three concentric spherical metallic shells A , B and C of radii a , b and c (a<b<c)have charge densities σ,−σandσ respectively . If the shells A and C are at the same potential then the relation between a , b and c is

    2. Relevant equations
    ##V##=##\frac{Q}{4πε0r}##

    3. The attempt at a solution
    I know the solution
    shells.png

    nation.png

    but I want to know what does it mean potential of shell A or potential of shell B,I mean what value I shall put in place of r in the formula
    ##V##=##\frac{Q}{4πε0r}## for shell A,B and C?
    Does potential of shell A or potential of shell B etc mean potential at the surface of shell A ,B respectively ?
     
    Last edited: Nov 11, 2015
  2. jcsd
  3. Nov 11, 2015 #2

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes.
    You mislead yourself by coloring in the volume of A and the volume between B and C.

    There is no formula ##V = \frac{1}{4πε_0r}##; typo :biggrin: ?

    But the r in ##V = \frac{Q}{4πε_0r}## is a for A, b for B and c for C :smile: .

    And the potential at a position ##\vec r## is the energy per Coulomb it takes to move a test charge from infinity (Where V = 0) to the position ##\vec r##
     
  4. Nov 11, 2015 #3
    Were you answering this
     
  5. Nov 11, 2015 #4

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes
    Note that you can't use this for A due to the presence of B and C, nor for B due to the presence of C.
    You see that in the solution at the first ##\therefore##

    I've always wanted to use that symbol ##\therefore## ! this is the first time :cool:
     
    Last edited: Nov 11, 2015
  6. Nov 11, 2015 #5

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Yes.

    In electrostatics, the potential of a conductor is uniform throughout the conductor.
     
  7. Nov 12, 2015 #6
    Did you mean potential of a conductor is same anywhere inside the conductor as well as on the surface of the conductor?
     
  8. Nov 12, 2015 #7

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Everywhere in the conducting material itself, as well as on the surfaces.
     
  9. Nov 12, 2015 #8

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Easy to remember: a conductor conducts. If there would be a potential difference, charge would be conducted until there's no more potential difference.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Potential in case of concentric shells program
Loading...