Let the current in the loop be
I.
The upper branch has two
1 Ω resistors in series, so its resistance is
1+1=2 Ω.
The cells have emfs
E2=12 V and
E1=4 V opposing each other, so the net emf driving the current is
E2−E1=12−4=8 V.
The lower branch contains an
8 Ω resistor.
Thus the total resistance of the loop is
2+8=10 Ω.
Using Ohm's law,
I=total resistancenet emf=108=0.8 A.
The potential difference between
P and
Q is the voltage across the
8 Ω resistor.
So,
VPQ=I×8=0.8×8=6.4 V.
Hence the current is
0.8 A and the potential difference between
P and
Q is
6.4 V.
Therefore, the correct option is
0.8 A, 6.4 V.