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Electric field question

  1. Oct 27, 2009 #1
    1. The problem statement, all variables and given/known data

    A grounded metal sphere is placed inside an original uniform electric field. Complete the electric field lines and determine the total net charge on the metal sphere (zero/pos or neg).

    3. The attempt at a solution

    I was thinking the electric field lines would enter then exit the sphere perpendicular to the sphere's surface. So i thought the total net charge would then be zero.

    Any help, thoughts, or guidence?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 27, 2009 #2
    You got the field lines being perpendicular right --- if the sphere is grounded from the left, then the charges that lean towards the left (in this, positive charges) will promote a voltage difference with the ground; so there is a good chance the sphere will be left with some charge.
  4. Oct 27, 2009 #3

    Andrew Mason

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    Is this a hollow or a solid metal sphere?

  5. Oct 27, 2009 #4
    My understanding is that this is a hollow sphere.

    I pretty sure that when an uncharged conductor is placed in an electric field, the electric field lines will look like i drew above, making the charges move left, thus making the object polarized. I just dont know/understand what effect grounding the object does to the object or the electric field lines.

  6. Oct 27, 2009 #5

    So, with the charges moving left making the object's right side positive, would the ground give the object more charges to offset the positives on the right?
  7. Oct 27, 2009 #6
    Yup...the potential difference with the ground would allow electrons to move into the sphere and offset the positive charge distribution. This would leave the sphere with a negative charge distribution.
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