Q. A certain loudspeaker(ssumed to be a point source) emits 30 W of sound power. A small microphone of effective cross-sectional area 0.75 cm² is located 200 m from the loudspeaker such that surface of microphone is in normal direction to wave propagation.Calculate:

 (a)the sound intensity at microphone,

 (b)the power received by the microphone.