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

Option B

`3* 10^(-5)`

Step-by-step 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* 1.2* 334* 1* 10^(-12)}=2.831* 10^(-5)\approx 3* 10^(-5)`