A hollow pipe of length 0.8 m is closed at one end. At its open end a ...
Frequency of 2nd harmonic of string = Fundamental frequency produced in the pipe
The mass of the string = μ l1
= 0.02 × 0.5 kg = 10g
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A hollow pipe of length 0.8 m is closed at one end. At its open end a ...
To find the fundamental frequency of the pipe, we can use the formula:
f = v/λ
where f is the frequency, v is the speed of sound, and λ is the wavelength.
Since the pipe is closed at one end, the fundamental frequency is given by:
f₁ = v/2L
where L is the length of the pipe.
Given that the length of the pipe is 0.8 m and the speed of sound is 320 m/s, we can substitute these values into the formula to find the fundamental frequency:
f₁ = 320/(2*0.8) = 200 Hz
Since the string resonates with the fundamental frequency of the pipe, the second harmonic of the string must also have a frequency of 200 Hz.
The frequency of the second harmonic of a string is given by:
f₂ = 2f₁
Substituting the value of f₁, we can find the frequency of the second harmonic:
f₂ = 2*200 = 400 Hz
To find the wavelength of the second harmonic of the string, we can use the formula:
λ = 2L/n
where λ is the wavelength, L is the length of the string, and n is the harmonic number.
Given that the length of the string is 0.5 m and the harmonic number is 2, we can substitute these values into the formula to find the wavelength:
λ = 2*0.5/2 = 0.5 m
Now, we can find the speed of the second harmonic of the string using the formula:
v = f₂ * λ
Substituting the values of f₂ and λ, we can find the speed of the second harmonic:
v = 400 * 0.5 = 200 m/s
Finally, we can find the tension in the string using the formula:
v = √(T/μ)
where v is the speed of the wave, T is the tension in the string, and μ is the linear mass density of the string.
Given that the speed of the wave is 200 m/s and the tension is 50 N, we can substitute these values into the formula to find μ:
200 = √(50/μ)
Squaring both sides of the equation, we get:
40000 = 50/μ
Rearranging the equation, we can solve for μ:
μ = 50/40000 = 0.00125 kg/m
Therefore, the linear mass density of the string is 0.00125 kg/m.
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