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Homework Help: Potential Energy of Dipole in Electric Field

  1. Jun 30, 2009 #1
    1. The problem statement, all variables and given/known data
    A dipole of moment 0.7 e * nm is placed in a uniform electric field with a magnitude of 50000 N/C. Find the potential energy of the dipole in the electric field at 60 degrees. Answer in units of J.

    2. Relevant equations
    -pE cos (theta)

    3. The attempt at a solution
    I found the magnitude of the torque on the dipole when it makes an angle of 60 degrees with the electric field to be 4.8497423e-24 N*m. (This I know to be correct.) I then used the equation -pE cos (theta) to get 2.8e-24 for the potential energy. However, I keep being told that this is incorrect.
  2. jcsd
  3. Jun 30, 2009 #2


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    Homework Helper

    Don't they give you the dipole moment p directly as a given "0.7 e * nm" ?

    Isn't that the dipole moment you use in

    U = -p*E*cosθ
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