A pipe open at both ends has a fundamental frequency of 220 Hz when the temperature is 0°C. (a) What is the length of the pipe? (b) What is the fundamental frequency at a temperature of 30°C?

Respuesta :

Explanation:

It is given that,

Fundamental frequency, f = 220 Hz

(a) We know that at 0 degrees, the speed of sound in air is 331 m/s.

For open pipe, [tex]\lambda=2l[/tex]

l is the length of pipe

Also,

[tex]v=f\lambda[/tex]

[tex]l=\dfrac{v}{2f}=\dfrac{331}{2\times 220}=0.75\ m[/tex]

(b) Let f' is the fundamental frequency of the pipe at 30 degrees and v' is its speed.

[tex]v'=331\sqrt{1+\dfrac{T}{273}}[/tex]

[tex]v'=331\sqrt{1+\dfrac{30}{273}}[/tex]

v' = 348.71 m/s

So, [tex]f'=\dfrac{v'}{\lambda}[/tex]

[tex]f'=\dfrac{348.71}{2\times 0.75}[/tex]

f' = 232.4 Hz

Hence, this is the required solution.

Answer:284.4 Hz

Explanation:

At [tex]o^{\circ}C[/tex] speed of sound is 331 m/s

and we know

[tex]Velocity\left ( v\right )=frequency\left ( f\right )\times wavelength\left ( \lambda\right )[/tex]

[tex]331=220\left ( 2L\right )[/tex]------[tex]\left ( \lambda =2L\right )[/tex]

L=0.613 m

[tex]\left ( b\right )[/tex]

[tex]v=v_0\sqrt{1+\frac{T}{273}}[/tex]

where velocity of sound at[tex]t=0^{\circ}C[/tex]

[tex]v=331\sqrt{1+\frac{30}{273}}[/tex]

v=348.7 m/s

for  frequency

[tex]v=f\lambda [/tex]

[tex]348.7=f\times 2\times 0.613[/tex]

f=284.4 Hz

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