posted by ayan .
Airplanes are noisy things. For example, if you stand really close to a runway, a military jet can produce a sound intensity of about 100 W/m2 at a distance of 30 m from the plane (this is beyond painful noise). You live near a military airport and want to work on physics with your friend. Since you don't want to shout, you decide to find a spot far enough away from the airport that the airplane noise is below the threshold of conversation (10−6 W/m2. How far do you need to go from the airport in kilometers to accomplish this?