Sound Waves Conceptual Question

[ca2010]

1. You are standing some distance from a jackhammer where the sound intensity is bearable. You then walk half the distance toward the jackhammer. The change in sound level is about:



The given answer is 6dB.



I am not sure if this problem requires knowing what intensity "bearable" is. I know that I=I₀(r₀/r)² so the intensity should increase fourfold. However I am not sure how to arrive at 6dB

 

[ehild]

It should be "just audible" instead of bearable. And you have to know the definition of "decibel" (dB) See http://hyperphysics.phy-astr.gsu.edu/hbase/sound/db.html

ehild