between $4 \Omega$ and $3 \Omega$

(in parallel), arc the same, $4 \times 1$ amp $=3 \times i_{1} \Rightarrow i_{1}=\frac{4}{3} A$

Total resistance of $4 \Omega$ and $3 \Omega=12 / 7 \Omega$

Current in $M Q P$ (upper one) $=1+\frac{4}{3}=\frac{7}{3} A$ $\therefore \quad P . D .=\frac{12}{7} \times \frac{7}{3}=4 V$

Current in $M N P=\frac{4}{1.25}=\frac{4 \times 4}{5}=\frac{16}{5} A$

$\therefore \quad$ P.D. across $1 \Omega=\frac{16}{5} A \times 1 \Omega=\frac{16}{5}$ volt

$\Rightarrow$ P.D. across $1 \Omega=3.2$ volt.