1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Two point charges and electric potential difference

  1. Nov 13, 2016 #1
    1. The problem statement, all variables and given/known data
    In an experiment modeling point charges I had to find equipotential lines. I did so using a voltmeter. The results looked like this: WIN_20161113_15_06_12_Pro.jpg
    Not a good quality picture, but the equipotential line on the right says 1.3 mV and the one on the left says 2.3mV. From this I had to calculate the value of the point charges. The idea is to compare theoretical calculations of the electric potential difference with the one I found to be -1mV. I chose two points along the line connecting the two point charges and named them A and B.
    2. Relevant equations
    Since point charges have a variable electric field the only option I had was to divide the separation between A and B into segments and use V=-Edx to find the potential difference in each segment.


    3. The attempt at a solution
    So I got confused because there are two point charges one that is positive and one that is negative. This means that I had to do calculations for both charges and then add them. I'm finding choosing the correct signs confusing so I reasoned that since the electric field created y both charges is in the same direction the signs for the electric field potential is the same. In other words both are negative. Is this reasoning correct. My final value for q was very small about 4.9*1^-15 C. The DC supply was 6V. Does this look right?
     
  2. jcsd
  3. Nov 14, 2016 #2

    andrevdh

    User Avatar
    Homework Helper

    The electric potential at a point in the electric field is just the algebraic sum of the potentials created by the two point charges.
     
  4. Nov 14, 2016 #3
    Thank you
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted