Two cells of emfs 1 V and 2 V and internal resistance 2 Ω and 1 Ω, respectively connected in parallel, gave a current of 1 A through an external…

Two cells of emfs $\displaystyle 1$ V and $\displaystyle 2$ V and internal resistance $\displaystyle 2 \Omega$ and $\displaystyle 1 \Omega$, respectively connected in parallel, gave a current of $\displaystyle 1$ A through an external resistance. If the polarity of one cell is reversed, then value of current through the external resistance will be $\displaystyle \frac{\alpha}{5} \mathrm{~A}$. The value of $\displaystyle \alpha$ is $\displaystyle \_\_\_\_$.