$\text{AT any instant the flux passing through the necklace is }\phi$

$\text{Average EMF induced in the necklace is }\xi = \frac{\Delta \phi}{\Delta t} = A\frac{\Delta B}{\Delta } = 0.01 \frac{1}{10^{-3}} = 10 V$

$\text{Total heat produced is }H = \frac{\xi^2}{R} T = \frac{10^2}{0.01}\times 10^{-3} = 10J$