Question

The physics of wind instruments is based on the concept of standing waves. When the player blows into the mouthpiece, the column of air inside the instrument vibrates, and standing waves are produced. Although the acoustics of wind instruments is complicated, a simple description in terms of open and closed tubes can help in understanding the physical phenomena related to these instruments. For example, a flute can be described as an open-open pipe because a flutist covers the mouthpiece of the flute only partially. Meanwhile, a clarinet can be described as an open-closed pipe because the mouthpiece of the clarinet is almost completely closed by the reed.

A. Consider a pipe of length 80.0 cm open at both ends. What is the lowest frequency f of the sound wave produced when you blow into the pipe?
B. A hole is now drilled through the side of the pipe and air is blown again into the pipe through the same opening. The fundamental frequency of the sound wave generated in the pipe is now_________ .
a. the same as before
b. lower than before
c. higher than before

Answer 1

1. 214.38hz

2. higher than before.

Step-by-step explanation:

1. the lowest frequency f of the sound wave produced

f = v/2L

l = 80cm = 0.8m

v = 343 metre per second, this is the sound speed of air

f = 343/2*0.8

the lowest frequency = 214.38hz

2. Since there is ahle n the pipe, this would shorten the length of air column that is able to oscillate in this pipe. we use the same formula as we used in question 1 here.

Vf ∝1/L

so we conclude that, c. it is higher than before