Solution:
Fundamental frequency of the closed organ pipe is
The natural frequencies of the closed organ pipe will be
Thus, the natural frequencies lies below the 1250 Hz is 6.
The number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are (Velocity of sound = 340 m )
Fundamental frequency of the closed organ pipe is
The natural frequencies of the closed organ pipe will be
Thus, the natural frequencies lies below the 1250 Hz is 6.