The figure shows a network of four resistors and three batteries. Which of the batteries is getting charged?

In a balanced Wheatstone's network,the resistances in the arms $Q$ and $S$ are interchanged. As a result of this:

In the given circuit,it is observed that the current $I$ is independent of the value of the resistance $R_6$. Then the resistance values must satisfy

In the circuit shown below,the ammeter reading is zero. Then the value of the resistance $R$ is (in $\Omega$)

Consider the circuit shown in the figure. The current $I_3$ is equal to

Four resistors $A, B, C$ and $D$ form a Wheatstone bridge. The bridge is balanced when $C = 100 \ \Omega$. If $A$ and $B$ are interchanged,the bridge balances for $C = 121 \ \Omega$. The value of $D$ is: (in $\Omega$)