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Homework Help: Electric potential difference question

  1. Oct 1, 2008 #1
    Two parallel horizontal plates are 0.4 cm apart in air. An oil droplet of m = 4.9*10^-17 kg is introduced between the plates. If the drop has 2 electronic charges and if there is no air buoyancy, you can hold the droplet motionless between the plates if you keep the potential difference between them at...?

    Do I use delta V = -int[E*dl] from a to b? How would I incorporate the mass?
  2. jcsd
  3. Oct 1, 2008 #2


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    For your first question, yes, that is the definition of electric potential.

    For your second question, the mass determines how much weight the electric field has to counteract.
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