Question

If the battery is being charged with a current of $5amp$, in what direction will current flow inside the battery, and what will be the reading of the voltmeter?

Answer 1

In charging a battery, a positive terminal of the battery is connected to a positve terminal of the charger. Hence, the current inside the battery is from anode to cathode.
The net change in potential energy for a charge $q$ making a round trip around a complete circuit must be zero. Hence, the net change in potential around the circuit must also be zero. In other words, the algebraic sum of potential difference and emfs around the loop is zero
Considering the section ab
$V_a-Ir+E=V_b$
or $V_a-V_b=V_{ab}=E+Ir$
or $V_{ab}=12+5\times 2=22volt$