A particular person's eardrum is circular, with a diameter of$8\mathrm{.}30$mm$.($a$)$How much sound energy $($in J$)$ is delivered to an eardrum in one second, at the threshold of human hearing? $($The threshold of human hearing is taken to be$1\mathrm{.}001012$W$/$m$2.)$J$($b$)$How much sound energy $($in J$)$ is delivered to an eardrum in one second, at the pain threshold for human hearing? $($The pain threshold occurs at $1\mathrm{.}00$ W$/$m$2,$ one trillion times as intense as the lowest audible level.$)$J$($c$)$Assume that musicians onstage are exposed to sound that is $10$ decibels below the human pain threshold. Over the course of a two$-$hour concert, how much sound energy $($in J$)$ does each ear absorb onstage?$$J$($d$)$Assume that the amplifiers on the stage operate at a combined power of $5,000$ Watts, and that $80\%$ of this is converted to sound. Which of the following best$$approximates$$the$$fraction$$of this power incident upon each eardrum onstage? As in the previous part, assume that the musicians are exposed to sound that is$10$ dB$$below the human pain threshold.one thousandth $(103)$one millionth $(106)$one billionth $(109)$one trillionth $(1012)$