Question

Two people are talking at a distance of 3.0 m from where you are and you measure the sound intensity as 1.1 × 10-7 W/m2. Another student is 4.0 m away from the talkers. What sound intensity does the other student measure? Assume that the sound spreads out uniformly and undergoes no significant reflections or absorption.

Answer 1

Answer:$I_2=0.618\times 10^{-7} W/m^2$

Explanation:

Given

Distance between source and  receiver $d_1=3 m$

Sound Intensity $I_1=1.1\times 10^{-7} W/m^2$

Distance of of second observer $d_2=4 m$

Intensity varies as

$I\propto \frac{1}{d^2}$

using this

$I=\frac{k}{d^2}$

$\frac{I_1}{I_2}=\frac{d_2^2}{d_1^2}$

$\frac{1.1\times 10^{-7}}{I_2}=\frac{4^2}{3^2}$

$I_2=0.75^2\times 1.1\times 10^{-7}$

$I_2=0.618\times 10^{-7} W/m^2$