Equivalent Resistance of Cube of Resistors: A to B

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The discussion revolves around finding the equivalent resistance between points A and B in a cube of resistors, each with resistance value "R." There is skepticism about the book's solution, which suggests parallel combinations that some participants believe are incorrect. However, others argue that the use of symmetry in the circuit allows for the correct simplification of the problem. The symmetry plane through points ABGH indicates that certain points can be connected, leading to a valid solution. Ultimately, the consensus is that the book's answer is indeed correct.
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Homework Statement


Here is a cube of resistors with each resistance of value "R".Find the equivalent resistance between A and B.

attachment.php?attachmentid=66606&stc=1&d=1392346578.jpg


Homework Equations


The Attempt at a Solution



My book says the equivalent circuit of the cube is :

attachment.php?attachmentid=66607&stc=1&d=1392346578.jpg


But i don't think it is correct.They have made parallel combinations which don't seem right.Is the book correct??
 

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you need to make your figures smaller. They are HUGE.

I agree w/ you that it doesn't seem correct but I'm guessing they are using some trick of symmetry in the redrawing.
 
The plane through the points ABGH is a symmetry plane, so the potentials of the points D and E must be equal, so you can connect them with a wire. Same for the points C and F.
 
willem2 said:
The plane through the points ABGH is a symmetry plane, so the potentials of the points D and E must be equal, so you can connect them with a wire. Same for the points C and F.

O,thanks a lot :smile:
 
nil1996 said:

Homework Statement


Here is a cube of resistors with each resistance of value "R".Find the equivalent resistance between A and B.

View attachment 167327

Homework Equations


The Attempt at a Solution



My book says the equivalent circuit of the cube is :

View attachment 167328

But i don't think it is correct.They have made parallel combinations which don't seem right.Is the book correct??
I realize this is a decade old thread but I checked it and it is correct.
 
Last edited:
bob012345 said:
I realize this is a decade old thread but I checked it and it is correct.
I thought of your simulations when I saw this thread pop up! :smile:
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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