A) 260 Hz
B) 130 Hz
C) 390 Hz
D) 520 Hz.
Correct Answer: A
Solution :
[a]: A cylindrical tube open at both the ends, its fundamental frequency is where v is the velocity of sound in air. \[\upsilon =\frac{v}{\lambda }=\frac{v}{2L}=390Hz\] (i) If a (1/4)th of cylindrical tube is immersed in a water, it will become a closed pipe of length three-fourth that of an open pipe as shown in figure (ii). Therefore, its fundamental frequency is \[\upsilon '=\frac{v}{\lambda '}=\frac{v}{3L}\] \[\upsilon '=\frac{v}{3L}=\frac{2}{3}\left( \frac{v}{2L} \right)=\frac{2}{3}\times 390Hz\](using (i)) = 260 Hz.You need to login to perform this action.
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