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Homework Help: Electric field given electric potential

  1. Feb 21, 2008 #1
    [SOLVED] electric field given electric potential

    1. The problem statement, all variables and given/known data

    The electric potential in a region of space is V = ( 210 x^{2} - 170 y^{2} ) V, where x and y are in meters.

    What is the strength of the electric field at ( 1.00 m, 3.00 m ) ?

    2. Relevant equations

    E = -dV/ds

    3. The attempt at a solution

    1. i know i have to find the derivative of the that given equation but i can't figure out where to start....because there are two different variable given....and i don't know in term of which variable i have to find the derivative
  2. jcsd
  3. Feb 21, 2008 #2


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    The E-field is a vector quantity and is given by the negative gradient of the potential.

    [tex] \mathbf{E} = -\nabla V [/tex]

    the [itex]\nabla[/itex] operator is:

    [tex] \nabla = \frac{\partial}{\partial x} \mathbf{\hat{i}} + \frac{\partial}{\partial y} \mathbf{\hat{j}} +\frac{\partial}{\partial z} \mathbf{\hat{k}}[/tex]
    Last edited: Feb 21, 2008
  4. Feb 22, 2008 #3
    thank you
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