$=9000 kg / m ^{2}$

$( A = CSA$ of wire $)$

$\left( Y =9 \times 10^{10} Nm ^{2}\right)$

$\left(\right.$ Strain $\left.=4.9 \times 10^{-4}\right)$

$\Rightarrow L =1 m =\frac{\lambda}{2} \Rightarrow \lambda=2 m$

$\Rightarrow v=f \lambda \Rightarrow \sqrt{\frac{T}{\mu}}=f \lambda$

Where $Y=\frac{T / A}{\text { strain }} \Rightarrow T=Y . A .$ strain

$\Rightarrow \sqrt{\frac{ Y . A . strain }{ m / L }}= f \times 2 \Rightarrow \sqrt{\frac{ Y . A I . \text { strain }}{ M }}= f \times 2$

$\Rightarrow \sqrt{\frac{ Y \times V \times \text { strain }}{ M }}= f \times 2 \Rightarrow \sqrt{\frac{ Y \times \text { strain }}{\rho}}= f \times 2$

$f =\frac{1}{2} \sqrt{\frac{ Y \times \text { strain }}{\rho}}=\frac{1}{2} \sqrt{\frac{9 \times 10^{10} \times 4.9 \times 10^{-4}}{9000}}$

$f=\frac{1}{2} \sqrt{\frac{9 \times 10^{3}}{9} \times 4.9}=\frac{1}{2} \sqrt{4900}=\frac{70}{2}=35 Hz$