Step 1: Analyze the circuit and use Kirchhoff's Voltage Law. Given \(PQ = 4V\), each \(60 \, \Omega\) resistor equally shares the voltage drop when combined with the \(8 \, \Omega\) resistor in parallel circuits. Step 2: Calculate the potential difference across \(A\) and \(B\). Given the potential difference across \(PQ\), the total resistance in parallel with PQ can be considered equivalent to a voltage source of 4V extended through multiple resistors:
\[
V_{AB} = V_{PQ} + \text{additional voltage drops across similar paths}.
\]
Considering a 3:1 ratio of the entire circuit setup based on resistor arrangements:
\[
V_{AB} = 3 \times V_{PQ} = 3 \times 6V = 18V.
\]
