A straight line source of sound of length `L=10m`, emits a pulse of sound energy (in mW) is intercepted by an acoustic cylindrical detector of surface area `2.4cm^2`. Located at a perpendicular distance 7 m from the source ? The waves reach perpenduculary at the surface of the detector. The total emiited by the source in the form of sound is `2.2xx10^(4)W`. (use `pi=22//7`)

Explanation

Imagine a cylinder of radius 7m and length 10m.Intensity of sound at the surface of cylinder is same everywhere.
Therefore `I=P/(2pirL)=(2.2xx10^4)/(2pixx10xx7)`
(As sound is propagating radially out only, sound energy does not flow out through the ends)
`therefore I=50 W//m^2`
Energy intercepted by the detector
`=IxxA =12mW`