The figure shows a part of an electric circuit. The potentials at points $a$,$b$,and $c$ are $30\,V$,$12\,V$,and $2\,V$ respectively. The current through the $20\,\Omega$ resistor will be $........\,A$.

The current through the $2 \Omega$ resistor of the given circuit is . . . . . . $mA$.

In the Wheatstone's bridge (shown in figure) $X = Y$ and $A > B$. The direction of the current between $a$ and $b$ will be

In the cube shown,current $i$ enters at $H$ and leaves at $C$. If $i_{AB} = \frac{i}{6}$,$i_{DC} = \frac{2i}{3}$,$i_{HA} = \frac{i}{2}$,$i_{GF} = \frac{i}{6}$,and $i_{HE} = \frac{i}{6}$,choose the branch in which the current is zero.

The four arms of a Wheatstone bridge have resistances as shown in the figure. $A$ galvanometer of $15\, \Omega$ resistance is connected across $BD$. Calculate the current through the galvanometer when a potential difference of $10\, V$ is maintained across $AC$.

The figure below shows a portion of an electric circuit with the currents in amperes and their directions. The magnitude and direction of the current in the portion $PQ$ is