Twelve resistances each of resistance R are connected in the circuit as shown in fig. Net resistance between points A and C would be

Explanation

Connect a cell across `A` and `B` Let current `I` enter as `A` and linear at `C` from symmetry the potentials at point `B,G,E and D` will be the same hence no current in current flow in acts `BG and ED` therefore the resistance of these arms become ineffictive The equivalent circuit of the given circuit will be THe effective resistance between `A and C` is
`(1)/(R ) = (1)/(4) + (1)/(6) + (1)/(4) = (4)/(12) or R = (12)/(8) = 1.5 Omega`