Question

A stopped pipe 1.00 m in length is filled with helium at 20∘C (speed of sound 999 m/s). When the helium in this pipe vibrates at its third harmonic frequency, it causes the air at 20∘C (speed of sound 344 m/s) in a nearby open pipe to vibrate at its fifth harmonic frequency. What is the frequency of the sound wave in the helium in the stopped pipe? Express your answer with the appropriate units.

Answer 1

Answer:

The frequency of the sound wave in the helium in the stopped pipe is 749.25 Hz.

Explanation:

Given that,

Length = 1.00 m

Temperature T = 20°C

Speed of sound = 999 m/s

We need to calculate the frequency of the sound wave in the helium in the stopped pipe

Using formula of frequency

$f_{He}=\dfrac{3 v_{He}}{4L}$

Put the value into the formula

$f_{He}=\dfrac{3\times999}{4\times1}$

$f_{He}=749.25\ Hz$

Hence, The frequency of the sound wave in the helium in the stopped pipe is 749.25 Hz.