
$ - 2i + 8 - 4 - 1 \times i - 9i = 0$ $ \Rightarrow $ $i = \frac{1}{3}A$
Potential difference across $PQ$ $ = \frac{1}{3} \times 9 = 3\,V$




$(A)$ The current through $P Q$ is zero.
$(B)$ $I_1=3 A$.
$(C)$ The potential at $S$ is less than that at $Q$.
$(D)$ $I _2=2 A$.