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Magnetic sphere in electrolyte

  1. Oct 24, 2005 #1
    If you have a metal sphere of the order of a say, few micrometers in diameter, and you put it in an electrolyte solution - what would you expect to happen when a current is passed through that solution? I am referring here to charges on the surface of the sphere.
  2. jcsd
  3. Oct 24, 2005 #2
    Well the sphere would get electrically charged?
  4. Oct 25, 2005 #3


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    The sphere will be possibly in the circuit but charges will go once the current will stop.
  5. Nov 4, 2005 #4
    You want this sphere to continue being charged once the current has stopped flowing?
  6. Nov 5, 2005 #5
    The applied voltage would create an electric field across the microsphere. Since it's a good conductor, electrons/holes in the metal would re-arrange to try to cancel the electric field. Ions in solution would be attracted to these charges, sheilding their effect.
    Code (Text):
    electrode                                                      electrode
    +    ------> current, +ion motion                              -
    +   <------  -ion motion                                      -
    +                                                             -
    +              +             -                                 -
    +            +     -     +                                   -
    +                -   ball  +     - free ions               -
    +          +     -         +                                 -
    +                  -      +       -                         -
    +            +                 -                              -
    (note the distinction between the current ions, and the "stationary" ions shielding the sphere)
    These are relatively small effects; consider that you have only 2-3V across several cm of electrolyte (small electric field). Ignoring the ion current (which has no not charge), this can be treated as a simple problem of electrostatics: a metal sphere surrounded by a dielectric, in an applied E field - you can solve this with an expansion in spherical harmonics.
    Last edited by a moderator: Nov 5, 2005
  7. Nov 6, 2005 #6
    And if you set that ball in motion in a strait line, which way would it bend? Or would the elctric charge not affect it?
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