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Intensity of sound wave

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Find the intensity(I) of sound wave whose frequency is 250 Hz. The displacement amplitude of particles of the medium at this position is 1 × 10$^{–8 }$m. The density of the medium is 1 kg/m$^3$ , bulk modulus (B) of elasticity of the medium is 400 N/m$^2$ .

I know I=2$(\pi f A)^2 \rho v$
And v $=\sqrt {B/\mu}$
Where $\mu = $ mass per unit length .

But I could not understand how to use them .

asked Jan 4, 2017 in Physics Problems by koolman (4,286 points)
You seem to have all the equations and data which you need. Put in the values and calculate the answer. I don't understand the difficulty.

$\mu$ should be density, not mass per unit length.
Here what is amplitude ?
*The displacement amplitude of particles of the medium at this position is 1 × 10^–8 m. *

1 Answer

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Best answer

I=2$(\pi f A)^2 \rho v$
And v $=\sqrt {B/\mu}$
Where $\mu = $ mass per unit volume .

Hence v =20m/s
And I =2$\pi ^2 (250)^2(10^{-8})^2 20$
I =$2.46$ x$10^{-9}W/m^2$

answered Jan 5, 2017 by koolman (4,286 points)
edited Jan 5, 2017 by koolman
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