Question

In an open organ pipe, the fundamental frequency is 30Hz. If the organ pipe is closed at one end, the fundamental frequency will be

• A. 10Hz
• B. 20Hz
• C. 30Hz
• D. 15Hz

Answer 1

Answer: (D)

15Hz

In an open pipe fundamental frequency ${\nu }_o=\frac{v}{2L}=30Hz$ -----(1)

In an closed pipe of same length fundamental frequency

${\nu }_c=\frac{v}{4L}=\frac{1}{2}\left(\frac{v}{2L}\right)=\frac{1}{2}\times 30$ ( From (1) )

$=15Hz$