A battery of $\mathrm{emf} E_0= 6 V$ is connected across a $2 m$ long uniform wire having resistance $4 \Omega /m$. The cells of small $\mathrm{emf} {\epsilon }_1=2V \mathrm{and} {\epsilon }_2=3 V$ having internal resistance $2 \Omega \& 1 \Omega$ respectively are connected as shown in the figure. The null point will be obtained at