https://drive.google.com/open?id=0B3IenBvKWb4PZW9rRWg4cXptT2c I had to find the resistance of this circuit between A and B. My teacher said that since the blank wires have zero resistance, the potential difference across the ends of the blank wire is zero(according to v = ir) and thus 1,4 are equipotent and 2,5 are equipotent and the circuit is thus simplified.The equivalent resistance comes out to be 2r/5. MY QUESTION:Will charge flow only through the circuit having resistance or will it flow through the circuit having no resistance or will it flow though both the branches. MY REASONING:Actually i am confused. One way in which i can reason is:the potential difference across each branch of a parallel circuit is same and in this case it is 0 and hence no current can flow thorough 1-4 and 2-5. Second way i can reason is that current always chooses the least resistant path and hence all the current will flow through 1-4 and 2-5.