Question

Suppose a certain jet plane creates an intensity level of 118 dB at a distance of 5.42 m. What intensity level does it create on the ground directly underneath it when flying at an altitude of 2.48 km?

Answer 1

Change in intensity in db = 10 log (distance near / distance far)^2
= 10 log (5.42/2480)^2
= 10 log (4.78 x 10^ -6)

= 10 (-5.321)
= - 53.21 db

Therefore the new intensity level is 118-53.21 =64.791 db

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