Potential of two points how are they same?

1. Jun 2, 2012

nishantve1

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

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

E G and D are at the same potential

and in this image

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
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. Jun 2, 2012

ehild

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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3. Jun 2, 2012

nishantve1

Thank you ! So much respect .

4. Jun 2, 2012

nishantve1

Just a little more help . Please explain whats up with this one

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
5. Jun 2, 2012

ehild

It is a mirror plane again...

ehild

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