The figure shows a network of five resistances and two batteries. The current through the $15\,V$ battery is .............. $A$.

Assertion : Kirchhoff's junction rule follows from the conservation of charge.
Reason : Kirchhoff's loop rule follows from the conservation of momentum.

In a Wheatstone bridge (see figure),resistances $P$ and $Q$ are approximately equal. When $R = 400 \,\Omega$,the bridge is balanced. On interchanging $P$ and $Q$,the value of $R$ for balance is $405 \,\Omega$. The value of $X$ is close to ................. $\Omega$. (in $.5$)

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

The potential difference $(V_A - V_B)$ between the points $A$ and $B$ in the given figure is (in $V$)

In the circuit diagram shown below,the magnitude and direction of the flow of current respectively would be