An open pipe closed at one end produces its first fundamental note. If the velocity of sound in air is P and t the length of the pipe; the frequency of the note is?

A. 2v/l
B. v/5l
C. v/4l
D. v/2l

Correct Answer:

Option C = v/4l

Explanation

In vibration in a closed pipe/tube, as shown in the figure, fundamental note is produced at the first position of resonance. When the length of the air column L = λ/4; => λ = 4L. Since the open end of the tube is taken as an antinode; and closed-end as the node.
Thus the associated frequency is given by
f = V/λ = V/4L
∴ f = V/4L