Current Electricity

Two cells of emfs $E_1$ and $E_2$ and internal resistances $r_1$ and $r_2\left(E_2>E_1\right.$ and $\left.r_2>r_1\right)$ respectively, are connected in parallel as shown in figure. The equivalent emf of the combination is $\mathrm{E}_{\text {eq. }}$. Then