\( \Rightarrow {\nu ^2} = \frac{{{P^2}}}{{4{l^2}}}\left[ {\frac{F}{m}} \right]\)
\(\therefore m \propto \frac{F}{{{l^2}{\nu ^2}}}\)
\( \Rightarrow [m] = \left[ {\frac{{ML{T^{ - 2}}}}{{{L^2}{T^{ - 2}}}}} \right] = [M{L^{ - 1}}{T^0}]\)
$3.29 \,cm, 3.28\, cm, 3.29 \,cm, 3.31 \,cm,$ $ 3.28\, cm, 3.27 \,cm, 3.29 \,cm, 3.30\, cm$