\(60=\sqrt{\frac{ T }{10 \times 10^{-3}} \times 0.5}\)
\(T =\frac{(60)^{2} \times 10^{-2}}{0.5}=72\,N\)
\(\Delta \ell=\frac{ F \ell}{ AY }=\frac{72 \times 0.5}{2 \times 10^{-6} \times 1.2 \times 10^{11}}\)
\(=\frac{72 \times 5}{24} \times 10^{-5}=15 \times 10^{-5}\)