12-1. The intensity of a sound produced by a point source decreases as the square of the distance from the source. Consider a riveter as a point source of sound and assume that the intensities listed in Table are measured at a distance Im away from the source . What is the maximum distance at which the riveter is still audible? (Neglect losses due to energy absorption in the air.) 12-2. Referring to Table , approximately how much louder does busy street traffic sound than a quiet radio? 12-3.Calculate the pressure variation corresponding to a sound intensity of 10^-16W/cm^2. (The density of air at 0^circ C and 1 atm pressure is 1.29times 10^-3g/cm^3 for the speed of sound use the value 3.3times 10^4cm/sec.

12-1. The intensity of a sound produced by a point source decreases as the square of the distance from the source. Consider a riveter as a point source of sound and assume that the intensities listed in Table are measured at a distance Im away from the source. What is the maximum distance at which the riveter is still audible? (Neglect losses due to energy absorption in the air.)<br /><br />To find the maximum distance at which the riveter is still audible, we need to determine the intensity level at which sound becomes inaudible. Typically, the threshold of hearing is around 0 dB. Assuming the intensity of the riveter at a distance Im is given in the table, we can use the inverse square law to find the maximum distance.<br /><br />The inverse square law states that the intensity of a sound is inversely proportional to the square of the distance from the source. Mathematically, this can be expressed as:<br /><br />I = k / r^2<br /><br />where I is the intensity, k is a constant, and r is the distance from the source.<br /><br />Given that the intensity of the riveter at a distance Im is known, we can rearrange the equation to solve for the maximum distance at which the riveter is still audible:<br /><br />r_max = sqrt(k / I)<br /><br />By substituting the given intensity value from the table into the equation, we can calculate the maximum distance at which the riveter is still audible.<br /><br />12-2. Referring to Table, approximately how much louder does busy street traffic sound than a quiet radio?<br /><br />To determine how much louder busy street traffic sounds compared to a quiet radio, we need to compare their respective intensity levels. The intensity level of a sound is measured in decibels (dB), which is a logarithmic scale.<br /><br />The decibel scale is defined as:<br /><br />L = 10 * log10(I / I_0)<br /><br />where L is the intensity level in decibels, I is the intensity of the sound, and I_0 is the reference intensity, typically taken as the threshold of hearing (0 dB).<br /><br />By comparing the intensity levels of busy street traffic and a quiet radio from the table, we can calculate the difference in decibels using the formula:<br /><br />ΔL = L_traffic - L_radio<br /><br />where ΔL represents the difference in intensity levels between busy street traffic and a quiet radio.<br /><br />12-3. Calculate the pressure variation corresponding to a sound intensity of $10^{-16}W/cm^{2}.$ (The density of air at $0^{\circ }C$ and 1 atm pressure is $1.29\times 10^{-3}g/cm^{3}$ for the speed of sound use the value $3.3\times 10^{4}cm/sec.$<br /><br />To calculate the pressure variation corresponding to a given sound intensity, we can use the relationship between pressure and intensity:<br /><br />P = sqrt(2 * I * ρ * c^2)<br /><br />where P is the pressure variation, I is the sound intensity, ρ is the density of the medium, and c is the speed of sound.<br /><br />Given the sound intensity of $10^{-16}W/cm^{2}$, the density of air at $0^{\circ }C$ and 1 atm pressure as $1.29\times 10^{-3}g/cm^{3}$, and the speed of sound as $3.3\times 10^{4}cm/sec$, we can substitute these values into the equation to calculate the pressure variation:<br /><br />P = sqrt(2 * $10^{-16}W/cm^{2}$ * $1.29\times 10^{-3}g/cm^{3}$ * ($3.3\times 10^{4}cm/sec$)^2)<br /><br />By performing the calculation, we can determine the pressure variation corresponding to the given sound intensity.