A body is suspended from a string of length 1   m and mass 2   g . The mass of the body to produce…

Mass per unit length of the given string is $\mu =\frac{m}{l}=\frac{2\times {10}^{-3}}{1}=2\times {10}^{-3} \mathrm{kg} {\mathrm{m}}^{-1}$

Speed of transverse waves on a string is given by,

$v=\sqrt{\frac{T}{\mu }}=\sqrt{\frac{mg}{\mu }}$

Fundamental frequency on a string fixed at both ends is given by,

$$\begin{gathered} f_0=\frac{v}{2l}=\frac{\sqrt{\frac{mg}{\mu }}}{2l} \\ \Rightarrow m=\frac{4l^2{f_0}^2\mu }{g}=\frac{4\times 1\times {10}^4\times 2\times {10}^{-3}}{10}=8 \mathrm{kg} \end{gathered}$$