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Charged insulator in contact with conductor

  1. Jun 2, 2017 #1
    1. The problem statement, all variables and given/known data
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    2. Relevant equations


    3. The attempt at a solution

    This is a quite a fundamental question in electrostatics and I felt pretty embarrassed getting it wrong .I thought correct option was d) .

    Could someone help me understand how conductor could acquire charge as charges cannot move from insulator .

    Thanks .
     

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  2. jcsd
  3. Jun 3, 2017 #2

    haruspex

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    Unfortunately it is also quite flawed, so don't feel too badly. It does not say whether the conductor is grounded!
    If not, it might acquire a very small net positive charge from the insulator. At the same time, there would be a redistribution of charges, bringing negative charge close to the insulator and pushing positive charge to the far side.
    If it is grounded then b is right.
     
  4. Jun 3, 2017 #3
    Suppose conductor is not grounded , then which option do you think is most appropriate . What do you think about option d) ?
     
  5. Jun 3, 2017 #4

    haruspex

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    Bit of a toss-up between a and d. As I posted, I believe it would acquire some positive charge, but it might be very small. It depends how good a contact is made and over how great an area.
    Remember that, typically, the charge on the insulator will be just on the surface, because that's as far as it got when the charge was created (by friction, say). So it is perfectly possible to transfer it off that surface again.
     
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