The correct option is C
Internal resistance,
$\mathrm{r}=\left(\frac{\mathrm{E}-\mathrm{V}}{\mathrm{V}}\right) \mathrm{R}=\left(\frac{\ell_{2}-\ell_{1}}{\ell_{2}}\right) \mathrm{R}$
$=\left(\frac{0.15}{2.85}\right)(9.5) \Omega=0.5 \Omega$
The correct option is C
Internal resistance,
$\mathrm{r}=\left(\frac{\mathrm{E}-\mathrm{V}}{\mathrm{V}}\right) \mathrm{R}=\left(\frac{\ell_{2}-\ell_{1}}{\ell_{2}}\right) \mathrm{R}$
$=\left(\frac{0.15}{2.85}\right)(9.5) \Omega=0.5 \Omega$