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I have no idea what formula I'm supposed to use.I just want to know the concept that would allow me to get the answer. I know basic concepts of electricity like charge, currents, etc., but as far resistances go I know only about series and parallel. I tried looking for resistances in a circular loop but I didn't understand what was being explained. Also I didn't find any concept that helped me understand what was to be done, probably because I didn't understand them.I used some help from a different question and got the resistances but my answer wasnt correct.

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its not a part of my homework or anything. i just wanted to solve an old paper. but im stuck –  Keith Rebello Oct 16 '13 at 6:52
    
Even if it's not a homework assignment, the homework policy still applies. Please see meta.physics.stackexchange.com/questions/714/… –  Nathaniel Oct 16 '13 at 6:53
    
but cant i atleast get the concept that applies? –  Keith Rebello Oct 16 '13 at 6:55
    
You're allowed to ask homework questions, but only if you put in some effort to show us what you understand and what you don't. At the moment nobody can answer your question, because we don't know which of the concepts you are familiar with and which you aren't. If you can edit it to explain precisely where you're stuck, then it will be on topic. –  Nathaniel Oct 16 '13 at 6:58
    
okay thanks thats what i wanted to know.i know basic concepts of electricity like charge,currents,etc but as far resistances go i know only about series and parallel.i tried looking for resistances in a circular loop but i didnt understand what was being explained.also i didnt find any concept that helped me understand what was to be done probably because i didnt understand them. –  Keith Rebello Oct 16 '13 at 7:03
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Resistance can be taken as $$R = \rho \frac{l}{a}$$ where $rho$ is resistivity, $l$ is length of resistor and $a$ is cross sectional area of the resistor.

The above is asking you for a ratio of $R_1:R_2$ and you are given all the numbers in the question. Shapes within a circuit diagram can typically be ignored, the diagrams are only symbolic to inform you of how the pieces are connected.

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thanks i finally understood the concept –  Keith Rebello Oct 16 '13 at 11:08
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