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The intensity of the sound wave reaching your ear from a car radio 140 m away from you is 0.050 W/m2. The car drives toward you, so that the distance between you and the radio has decreased to one-fourth of its original value. Determine the new intensity of the sound reaching your ear.

Respuesta :

Answer: intensity (I2) = 0.8W/m²

Explanation: The relationship between the intensity of sound wave obeys the inverse square law, that's the intensity (I) is inversely proportional to square of distance (r).

I α r², I= kr²

I1 * (r1)² = I2 * (r2) ²

From the question,

I1 = 0.050W/m², r1 = 140m, I2 =?, r2= 1/4 * 140 = 35m.

By substituting the parameters, we have that

0.05 * (140)² = I2 * (35)²

0.05 * 19600 = I2 * 1225

980 = I2 * 1225

I2 = 980/1225

I2 = 0.8W/m²

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