\(n = \frac{1}{{2l}}\sqrt {\frac{T}{m}} \Rightarrow n \propto \frac{{\sqrt T }}{l} \Rightarrow \frac{{n'}}{n} = \sqrt {\frac{{T'}}{T}} \times \frac{l}{{l'}}\)
putting \(T' = T + 0.44T = \frac{{144}}{{100}}T\) and \(l' = l - 0.4l = \frac{3}{5}l\)
We get \(\frac{{n'}}{n} = \frac{2}{1}\).
(હવામાં ધ્વનિનો વેગ $330\;m/sec$ છે)
$[\,dB$ માં લબ્ધિ $\left.=10 \log _{10}\left(\frac{ P _{ o }}{ P _{i}}\right)\right]$