Question

he intensity of sound from a point source is 1.0 x10⁻⁸ W/m² at a distance of 5.0 m from the source. What will be the intensity at a distance of 25 m from the source?

Answer 1

Answer ⇒ Intensity at point 25 m away is 4 × 10⁻¹⁰ W/m².

Explanation ⇒ We know that the intensity is inversely proportional to the square of the distance from the source.

Thus,

I/I' = (d'/d)²

This means, Intensity I is at point d and Intensity I' is at point d'.

Thus, d = 5 m and d' = 25 m.

I = 10⁻⁸ W/m².

∴ 10⁻⁸/I' = (25/5)²

∴ 10⁻⁸/I' = 25

∴ I' = 4 × 10⁻¹⁰ W/m².

Hope it helps.

Answer 2

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