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Homework Help: Electric Field

  1. May 25, 2009 #1
    1. The problem statement, all variables and given/known data
    Two point charges of unknown magnitude and sign are places at some distance apart. The electric field is zero at a point not between them , but on the line joining the. Write 2 essential conditions for this to happen.

    2. Relevant equations
    E = q1*q2/(4 * pi * epsilon0 * r2)

    3. The attempt at a solution
    Since the net field is zero at a point outside the line joining the 2 charges ,
    they should be oppositely charged.

    So, condition one:
    The charges should be oppositely charged .

    What would be the second condition?

    Any help would be highly appreciated.
    Thank You.
    Last edited: May 25, 2009
  2. jcsd
  3. May 25, 2009 #2


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    Homework Helper

    The point should be nearer to the smaller charge.
  4. May 25, 2009 #3


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Hint: try finding the location of zero electric field when the charges are +1 C and -1 C, and 1 m apart.
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