Question

Two identical batteries,each of emf $2V$ and internal resistance r=1 $\Omega$ by passing a current through it. The maximum power that can be developed across $R=1\Omega$ using these batteries is

• A. $\frac{16}{9}W$
• B. $\frac{25}{9}W$
• C. $2W$
• D. $4W$

Answer 1

The correct option is A $\frac{16}{9}W$

When $m$ identical cells are connected in parallel,
$I=\frac{{ϵ}_i}{R+\frac{r_i}{m}}$
As two batteries are connected in parallel. ${ϵ}_1={ϵ}_2=2V$,$r_1=r_2=1.0\Omega ,R=1\Omega$
$I=\frac{2}{1+\frac{1}{2}}=\frac{4}{3}A$
Power developed resistance=$I^{2}R=\frac{16}{9}W$