Question

A siren is mounted high in the air and produces 10 W of sound power at 50 Hz. If you are 15 m away from this siren, how many phons would you register at your location?

A) 60 phons
B) 65 phons
C) 70 phons
D) 75 phons

Answer 1

To calculate the loudness in phons, use the formula: L = 40 log10(I/I0)+b. For a 60.0-Hz sound with a loudness of 60 phons, the intensity is approximately 0.0001 W/m2 (A). For a 10,000-Hz sound with a loudness of 60 phons, the intensity is also approximately 0.0001 W/m2.

Step-by-step explanation:

To calculate the loudness in phons, we can use the formula:

L = 40 log10(I/I0) + b

where L is the loudness in phons, I is the sound intensity in watts per meter squared, I0 is the reference intensity (10-12 W/m2), and b is a constant that depends on the frequency. For a 60.0-Hz sound with a loudness of 60 phons, we can use this formula to find the intensity:

60 = 40 log10(I/I0) + b

Solving for I, we find that the intensity is approximately 0.0001 W/m2.

For a 10,000-Hz sound with a loudness of 60 phons, we can use the same formula to find the intensity:

60 = 40 log10(I/I0) + b

Solving for I, we find that the intensity is approximately 0.0001 W/m2.