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Potential of two points how are they same?

  1. Jun 2, 2012 #1
    1. The problem statement, all variables and given/known data

    I am confused here .
    Each wire is of resistance R
    How in this image

    76xQa.png

    E G and D are at the same potential

    and in this image
    pzhfZ.png
    How A and F and Dand G are equivalent?

    2. Relevant equations

    I dont think any equations will be used in solving this but I guess V =IR might be

    3. The attempt at a solution

    In the first image what I figured out is since the points E G and D are at one resistor drop from H so they are at the same potential but I am not able to figure out in the second situation

    I am taking help of this website
    http://physicstasks.eu/uloha.php?uloha=285
    but its quiet confusing
    I JUST WANTED TO KNOW WHATS THE METHOD BEHIND FINDING POINTS WITH EQUAL POTENTIAL IN SUCH CASES ?
     
    Last edited: Jun 2, 2012
  2. jcsd
  3. Jun 2, 2012 #2

    ehild

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    Gold Member

    Symmetrically equivalent points are at equal potential. Those points are equivalent which transform into each other during a symmetry operation.
    Have you got a cube? Turning it around the body diagonal HB by 120° would not change anything: It looks the same as before. If you connect the battery to the points H and B, on the same axes, nothing happens again as the battery transforms into itself.
    In the other case, the battery is in the mirror plane EHCB. The point A is mirror image of F, and D, G are also mirror images to each other, so they are equivalent.

    ehild
     

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  4. Jun 2, 2012 #3
    Thank you ! So much respect .
     
  5. Jun 2, 2012 #4
    Just a little more help . Please explain whats up with this one
    1rjNe.png
    Where is the symmetry here if the Cell is connected btw A and B ?
    Also in the second figure why doesnt current flow through FG and AD ?
     
    Last edited: Jun 2, 2012
  6. Jun 2, 2012 #5

    ehild

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    It is a mirror plane again...

    ehild
     

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