From the given circuit diagram, the internal resistance of both the cells and resistance R connected in series.Consider current I is flowing through the circuit. We use Kirchhoff's voltage law for the closed path (ABCDA),
−0.2I+2−0.3I+2−0.1I=0⇒0.6I+4=0 ∴ I=
20
3
A Potential difference across cell x, V1−2+0.1×
20
3
=V2⇒V1−V2=
4
3
Potential difference acros cell y, V2−2+0.3×
20
3
=V3⇒V2−V3=0 Hence, the potential difference across cell y is zero.