Question

There is evidence that elephants communicate via infrasound, generating rumbling vocalizations as low as 14 Hz that can travel up to 10 km. The intensity level of these sounds can reach 104 dB, measured a distance of 4.1 m from the source. Determine the intensity level of the infrasound 10 km from the source, assuming the sound energy radiates uniformly in all directions.

Answer 1

Answer:

$L = 96.2 dB$

Explanation:

As we know that the level of intensity is given as

$\beta = 10Log(\frac{I}{I_o})$

here we know

$\beta = 104 dB$

$104 = 10Log(\frac{I}{10^{-12}})$

$I = 0.025 W/m^2$

now the sound is travelling in all possible directions so we have

$\frac{I_1}{I_2} = \frac{r_2^2}{r_1^2}$

$\frac{0.025}{I_2} = \frac{10^2}{4.1^2}$

$I_2 = 4.2 \times 10^{-3} W/m^2$

now for level of sound we have

$L = 10Log(\frac{4.2 \times 10^{-3}}{10^{-12}})$

$L = 96.2 dB$