A portable audio speaker has a power output of 8.00 W. If the speaker emits sound equally in all directions, what is the sound intensity at a distance of 2.00 m from the speaker? Express you

Respuesta :

Answer:

[tex]I=0.159\frac{W}{m^2}[/tex]

Explanation:

the formula to calculate the intensity, given the power:

[tex]I=\frac{P}{A}[/tex]

Where [tex]I[/tex] is intensity, and [tex]P[/tex] is the power that the wave carries in a given area [tex]A[/tex]. In this case:

[tex]P=8.00W[/tex], and the area since the speaker emits the sound equally in all directions is the area of a surface of a sphere with a radius of [tex]2.00m[/tex]:

[tex]A=4\pi r^2[/tex]

replacing the radius value:

[tex]A=4\pi (2.00m)^2[/tex]

[tex]A=4\pi (4m^2)[/tex]

[tex]A=16\pi m^2[/tex]

[tex]A=16(3.1426)m^2[/tex]

[tex]A=50.266m^2[/tex]

So, now that we know the area we can calculate the intensity:

[tex]I=\frac{P}{A}[/tex]

[tex]I=\frac{8.00W}{50.266m^2}[/tex]

[tex]I=0.159\frac{W}{m^2}[/tex]

the sound intensity at the distance of 2.00m from the speaker is [tex]I=0.159\frac{W}{m^2}[/tex]