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What is the Strength of the Electric Field?

  1. Mar 14, 2015 #1
    1. The problem statement, all variables and given/known data
    Specify the strength of the electric field. Let r = 7.3cm .



    2. Relevant equations
    E1= (k*p)/(r^2+a^2)^3/2
    Here k= constant used in Coulomb's law. a= half the length of dipole
    p= dipole moment = charge x length of dipole. Charge = 3nC and length of dipole



    3. The attempt at a solution
    E1= (9E9)(3E-9)/(.146)^2+(.073)^2)^(3/2)= 6207

    I got this wrong, but does anyone have any advice on how to solve this?
     

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    Last edited: Mar 14, 2015
  2. jcsd
  3. Mar 14, 2015 #2

    SammyS

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    It appears that you used the amount of charge for p, rather than dipole moment.

    ## p=2aq ##
     
  4. Mar 14, 2015 #3
    Then ((9E9)(2*.073*3E-9))/((.146^2)+(.073)^2)^(3/2) = 906?
     
  5. Mar 14, 2015 #4

    SammyS

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    I'm surprised that a problem like this would have a be larger than r. Usually it's the other way around.

    What is the complete problem you were given to solve? -- word for word.
     
  6. Mar 15, 2015 #5
    What are the strength and direction of the electric field at the position indicated by the dot in the figure (Figure 1) ?
    Specify the strength of the electric field. Let r = 7.3cm .
    Express your answer using two significant figures.
    Thats word for word.
     
  7. Mar 15, 2015 #6

    SammyS

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    In the figure, the charges have a separation, 2r . That is to say, a = r .

    physics-problem-png.80347.png
     
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