# Please help?

During a concert, a "Fa" note is played on a horn that has a frequency of 349 Hz. When using a pressure gauge, it marks me that the maximum pressure difference from the atmospheric pressure produced by this sound is 0.5 Pascal.

Calculate:

to). How much is the intensity of sound in decibels?

b). What is the wavelength of this sound? (Speed of sound in the air of 343 m / s).

C). What is the pressure equation as a function of time?

### 2 Answers

- VamanLv 72 months agoFavorite Answer
Hearing limit is p0= 20*10^(-6)

Decible =db= 10 log( p/p0)=10 log(0.5*10^6/20)=60 *0.025=1.5

Wave length= 343/349=0.12 m

For the pressure equation you need the amplitude value. I have to guess

Wave=sqrt(0.)5 sin wt, pressure will be square of the value= o0.5 sin^2 wt= 0.5/2(1- cos 2 wt)

=0.25 (1_ cos 2*2 pi*349 t)

This is all guess work. Verify with the answers you have.

thank you very much!