Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Uniform electric field in a triangular arrangement

  1. Jan 19, 2007 #1
    1. The problem statement, all variables and given/known data

    The drawing shows a uniform electric field that points in the negative y direction; the magnitude of the field is 1600 N/C.


    a) Determine the electric potential difference VB - VA between the points A and B.
    The answer here is 0 V.

    (b) Determine the electric potential difference VC - VB between the points B and C.

    (c) Determine the electric potential difference VA - VC between the points C and A.

    2. Relevant equations


    3. The attempt at a solution

    For A, delta(V)= -(1600N/C)(.06m)- -(1600N/C)(.06m)= 0V

    For B, I tried delta(V)= -(1600)(.08)- -(1600)(.08)=0V which is an incorrect answer according to my online submission.

    C hasn't been attempted yet, because I'm going to need to make sure I'm doing this correctly.

    I'm not sure how to determine the different potentials when I have no values for the point charges... Can anyone offer some assistance? Not looking for answers, just guidance that will get me on my way. Thanks!
  2. jcsd
  3. Jan 19, 2007 #2
    Can anyone help me out here?
  4. Jan 19, 2007 #3
    You used 0.8 twice in B) which would put both charges in the same place (in y).

    You want their separation, the amount the E field drops off with that distance. Which is linear according to the equation shown.

    (i think, im no physicist)
    Last edited: Jan 19, 2007
  5. Jan 19, 2007 #4
    I figured that using the 0.8 twice is part of my problem, but I'm honestly lost as to how to determine Vb and Va, etc. without any information about a charge at each of those points, let alone calculating delta(v) between those without any of that information. If someone could give me a clue on that, I can handle the rest. I've spent hours on this problem and I don't even think I'm looking at it correctly anymore.
  6. Jan 19, 2009 #5
    E=(delta(V)/delta(s)) where s is the distance between the points, it works for part b but i dont know about part c yet

    you switch it around to get delta(V)=E*delta(s)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook