First harmonic is obtained at
\(l=\frac{\lambda}{4}=50 \mathrm{cm}\)
Third harmonic is obtained for resonance,
\(l^{\prime}=\frac{3 \lambda}{4}=3 \times 50=150 \mathrm{cm}\)
(તારનો યંગ મોડ્યુલસ $Y =9 \times 10^{10}\, Nm ^{-2}$ )
$[\,dB$ માં લબ્ધિ $\left.=10 \log _{10}\left(\frac{ P _{ o }}{ P _{i}}\right)\right]$