Q: A tube, closed at one end and containing air, produces when excited, the fundamental note of frequency 512 Hz. If the tube is opened at both ends the fundamental frequency that can be excited is (in Hz)
(a) 1024
(b) 512
(c) 256
(d) 128
Ans: (a)
Sol: Fundamental frequency for closed organ pipe
$\large f_c = \frac{v}{4l} = 512 $ (given)
$\large f_o = \frac{v}{2l} = 2 (\frac{v}{4l}) $
$\large f_o = 2 \times 512 = 1024 Hz$