The intensity of a certain siren is 0.060 W/m^2 from a distance of 25 meters. What is the intensity of this siren at a distance of 50 meters

Question

The intensity of a certain siren is 0.060 W/m^2 from a distance of 25 meters. What is the intensity of this siren at a distance of 50 meters?

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Ngọc Khuê 5 years 2021-08-30T07:42:26+00:00 1 Answers 15 views 0

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  1. diemthu
    0
    2021-08-30T07:43:40+00:00
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    The intensity of siren is 0.015 W m⁻²

    Explanation:

    The intensity of sound is inversely proportional to the square of distance between source and the observer .

    Thus Intensity at a distance 25 m  is I₁ ∝ \frac{1}{r_1^2}                               I

    Similarly the intensity at a distance 50 m is I₂ ∝ \frac{1}{r_2^2}               II

    Dividing II by I , we have

    \frac{I_2}{I_1} = \frac{r_1^2}{r_2^2} = \frac{25^2}{50^2} = \frac{1}{4}

    Thus I₂ = \frac{1}{4} x 0.06 =  0.015 W m⁻²

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