Question

The frequency of the faintest audible sound is about 1,000Hz. What is the pressure variation corresponding to this sound.

A. 1x10^-12Pa

B. 3x1=^-5Pa

C. 5x10^-2Pa

D. 30.Pa

Answer 1

Answer:

Option B

$3\times 10^{-5}$

Explanation:

Variation of pressure, $\triangle P$ is given by

$\triangle P=\sqrt {2\rho vi}$

Where v is the speed of sound, i is the intensity, rho is the density of air whose value is taken as 1.2 Kg/m3

Taking the speed of sound in air as 334 m/s then

$\triangle P=\sqrt{2\times 1.2\times 334\times 1\times 10^{-12}}=2.831\times 10^{-5}\approx 3\times 10^{-5}$