A 20.0 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the frequency of the third mode of vibration?
A) 2,900 Hz
B) 2,480 Hz
C) 2,070 Hz
D) 1,660 Hz
E) 1,240 Hz

Question

Quizplus · Accepted Answer

The third mode of vibration for an organ pipe that is open at one end and closed at the other is given by: 
f = (3v/4L), where v is the speed of sound in air and L is the length of the pipe. 
Plugging in the values: 
f = (3 x 331/4 x 0.2) 
f = 2077.25 Hz ≈ 2,070 Hz 
Therefore, the answer is C) 2,070 Hz.

A 200 Cm Long Organ Pipe Is Filled with Air and and Is