Referring to the figure below,the effective resistance of the network is

$A$ 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 . . . . . . $\Omega$.

The lowest resistance which can be obtained by connecting $10$ resistors each of $1/10$ $\Omega$ is

The ratio of the equivalent resistance of the network (shown in figure) between the points $a$ and $b$ when the switch is open and when the switch is closed is $x : 8$. The value of $x$ is ..... .

An electrical cable consists of a single copper wire of radius $9 \ mm$. Its resistance is $5 \ \Omega$. If this cable is replaced by $6$ copper wires,each of radius $3 \ mm$,then the total resistance of the cable will be ............. $\Omega$.

$A$ wire has a resistance of $24\,\Omega$ and is bent into the shape shown in the figure. The effective resistance between $A$ and $B$ is .............. $\Omega$.