When \(\ell\) is \(\frac{\ell}{2}\) and radius is \(\frac{\mathrm{r}}{2}\)

\(\therefore \quad \mathrm{R}^{\prime}=\frac{\rho \ell{4}}{\pi 2 \mathrm{r}^{2}}=\frac{2 \rho \ell}{\pi \mathrm{r}^{2}}\)

So, \(\mathrm{R}^{\prime}=2 \mathrm{R}\) So, heat is doubled according to \(\mathrm{H}=\mathrm{I}^{2} \mathrm{RT}\)