Question

Can u pls find the effective resistance between A and C (see attached file)

Answer 1

this is an example of wheatstone bridge principle.so the resistance connected to B in the center is removed as no current flows through it.let BX be the removed resistance.AX and XC are in series which in combination are parallel to AC and also parallel to the series combination of AB and BC.hence 1+1 parallel 1+1 parallel 1=[(1/2+1/2+1/1)^{-1}]=1/2=0.5ohm

Answer 2

thks, i had the same answer but someone else kept insisting it is 3 ohm...