For the organ pipe closed at one end, the fundamental frequency of the wave of wavelength λ is given by n0 = v/4L The frequency of ith over tone is given by ni=(i+1) x n0 where i=1,2,3…. etc.
(a) n0 = V/4I
Wher n0 = frequency of the fundamental node
The first four overtones are 3n0 , 5n0 , 7n0 and 9n0
∴ So, the required frequencies are 550, 1650, 2750, 3850, and 4950 Hz.
The first overtones are 2n0, 3n0 , 4n0 and 5n0
So, the required frequency are 1100, 2200, 3300, 4400, and 5500 Hz
The frequency of the nth overtone is (n +1) n0 .
∴ (n +1) n0 =20000 or (n+1)100 = 20000
Or n = 17.18
The acceptable value is 17.