in a test of subsonic jet flies qver head at an altitude of 100 m the sound intensity on the ground as the jet passes overhead is 160 db .At wha let altitude shud d plane fly so that noise isss than 120 dbans 10 km plz explain
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3 Answers
6210 log(P1/P0)=160
10 log(P2/P0)=120
10 log(P1/P2) = 40
log(P1/P2) = 4
P1/P2=104
Pressure is inversely pro to R2
r2/r1=102
r2=100r1 = 10km
62Things to remember:
There is a "base"/"Reference" sound level.
pressure is inversely prop to the radius square (The logic hereis similar to guass law)
As the distance increases, area increases... as 4piR2
so the "Pressure" (Force/unit area) decreases in that ratio...
