d
Equivalent $\mathrm{emf}$ and resistance of $2 \mathrm{\,V}$ and $6 \mathrm{\,V}$ batteries
$\mathrm{E}^{\prime}=\frac{6 \times 1-2 \times 1}{1+1}=2 \mathrm{\,V} \quad $ and $ \quad \mathrm{R}^{\prime}=\frac{1}{2} \,\Omega$
Net $\mathrm{emf}$ $=2 \mathrm{\,V}$
