By which of the following single load resistance should the load bridge be replaced so that the power to the load remains unchanged (in $Omega$)? (Given $r = 3 \ \Omega$ for each resistor in the bridge)

$A$ wire of resistance $R$ is bent to form a square $ABCD$ as shown in the figure. The effective resistance between $E$ and $C$ is ( $E$ is the mid-point of arm $CD$ ).

The total current supplied to the circuit by the battery is . . . . . . . (in $A$)

The equivalent resistance between points $A$ and $B$ in the given network is ............ $\Omega$.

$A$ wire of resistance $20 \Omega$ is divided into $10$ equal parts. $A$ combination of two parts are connected in parallel and so on. Now,the resulting pairs of parallel combinations are connected in series. The equivalent resistance of the final combination is . . . . . . $\Omega$.

Three resistors each of $4\,\Omega$ are connected together to form a network. The equivalent resistance of the network cannot be ............ $\Omega$.