In the network shown in the figure,each of the resistance is equal to $2\,\Omega$. The resistance between the points $A$ and $B$ is .............. $\Omega$.

In the circuit shown in the figure,all the resistances are identical and each has the value $r \ \Omega$. The equivalent resistance of the combination between the points $A$ and $B$ will remain unchanged even when the following pairs of points marked in the figure are connected through a resistance $R$.

The effective resistance between points $A$ and $B$ is ............... $\Omega$.

If ${V_{AB}} = 4\,V$ in the given figure,then resistance $X$ will be .............. $\Omega$.

In the given circuit,the galvanometer reading is zero. If the internal resistance of the cells is negligible,then the value of $x$ is ............. $\Omega$.

In the circuit given,the correct relation for a balanced Wheatstone bridge is