Answer :
Answer:
Explanation:
We know that intensity of sound is inversely proportional to square of distance of point from the source .
For two points at distance of R₁ and R₂ , Intensity of sound I₁ and I₂ will vary as follows
I₁ / I₂ = R₂² / R₁²
I₁ = 2 W / m² , R₁ = 2 m , R₂ = 20m , I₂ = ?
Putting the values in the expression above
2 / I₂ = 20² / 2²
I₂ = (2 x 4) / 400
= .02 W / m²
Answer:
[tex]0.02W/m^2[/tex]
Explanation:
We are given that
Sound intensity,[tex]I_0=2W/m^2[/tex]
Distance,r=2 m
We have to find the intensity of sound for a person watching from 20 m away.
r'=20 m
[tex]\frac{I}{I_0}=\frac{r^2}{r'^2}[/tex]
[tex]\frac{I}{I_0}=\frac{2^2}{(20)^2}[/tex]
[tex]I'=I_0(\frac{4}{400})[/tex]
[tex]I=2\times \frac{100}[/tex]
[tex]I=0.02 W/m^2[/tex]
Hence, the sound intensity for a person watching from 20 m away=[tex]0.02W/m^2[/tex]