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s344n2d4d5 [400]

3 years ago

10

A very loud train whistle has an acoustic power output of 100 W. If the sound energy spreads out spherically, what is the intens

ity level in dB at a distance of 100 meters from the train?

1 answer:

valentina_108 [34]3 years ago

7 0

Answer

given,

Power output of loud train = 100 W

Distance of intensity level from train= 100 m

I₀ = 10⁻¹² W/m²

Intensity of sound = ?

we know,

$I = \dfrac{P}{Area}$

$I = \dfrac{P}{4\pi r^2}$

$I = \dfrac{100}{4\pi 100^2}$

$I =7.957\times 10^{-4}\ W/m^2$

Intensity level

= $10 log(\dfrac{I}{I_0})$

= $10 log(\dfrac{7.975\times 10^{-4}}{10^{-12}})$

= $10 \times 8.900$

= 89 dB

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