In the resonance experiment, two air columns (closed at one end) of 100 cm and 120 cm long, give 15

Question

In the resonance experiment, two air columns (closed at one end) of 100 cm and 120 cm long, give 15 beats per second when each one is sounding in the respective fundamental modes. The velocity of sound in the air column is\

Professor PC Thomas Classes · Answer

(b) : $l_{1}=100 \mathrm{~cm}, l_{2}=120 \mathrm{~cm}$ Frequency of beat = 15 beat / sec\ Fundamental frequency, $f=\frac{v}{4 l}$\ so, beat $=\left(f_{1}-f_{2}ight)$\ $15=\frac{v}{4}\left(\frac{1}{1}-\frac{1}{1.2}ight) ; 15 	imes 4=v\left(\frac{1.2-1}{1.2}ight)$\ $v=60 	imes 6=360 \mathrm{~m} / \mathrm{s}$\