Answer:
The intensity in 10-3 W/m2 at 39.3 m is [tex]0.26275*10^{-3}\ W/m^2[/tex]
Explanation:
Given Data:
frequency=1,054 Hz
intensity=6.429 mW/m^2
distance=7.945 m.
Required:
intensity in 10^-3 W/m^2 at 39.3 m=?
Solution:
Intensity at distance r from point source which is emitting sound waves of power P is given by the following formula:
Intensity=I=[tex]\frac{P}{4\pi r^2}[/tex]
Where:
P is the power
r is the distance
[tex]\frac{I_1}{I_2}=\frac{\frac{P}{4\pi r_1^2}}{\frac{P}{4\pi r_2^2}} \\\frac{I_1}{I_2}=\frac{r_2^2}{r_1^2} \\I_2=I_1*\frac{r_1^2}{r_2^2}[/tex]
[tex]r_1= 7.945 m\\r_2= 39.3 m\\I_2=6.429*10^{-3} *\frac{7.945^2}{39.3^2}[/tex]
[tex]I_2=0.00026275\ W/m^2\\I_2=0.26275*10^{-3}\ W/m^2[/tex]
The intensity in 10^-3 W/m2 at 39.3 m is [tex]0.26275*10^{-3}\ W/m^2[/tex]
