Thank you for reporting, we will resolve it shortly
Q.
The maximum current that flows in the fuse wire, before it blows out, varies with the radius $r$ as
BHUBHU 2008Electromagnetic Induction
Solution:
If $I$ is the safe current through the fuse wire and $h$ is the rate of loss of heat in steady state,
$I^{2} R=h A$
Or $I^{2}\left(\frac{\rho L}{\pi r^{2}}\right)=h \times 2 \pi r L$
Or $I \propto r^{3 / 2}$