The loudness in decibels of sound is defined as 10 log i/i0, where i is the intensity of the sound in watts per square meter (w/m2). i0, the intensity of a barely audible sound, is equal to 10 -12 w/m2. town regulations require the loudness of construction work not to exceed 100 db. suppose a construction team is blasting rock for a roadway. one explosion has an intensity of 1.65 x 10-2 w/m2. is the explosion in violation of town regulations? which physical value do you need to calculate to answer the question? what values should you use for i and i0

As the problem states, to solve this, we are going to use the equation 
where 
is the loudness in dB
is the intensity of a sound 
  is the minimum intensity detectable by the human ear

We know for our problem that ; we also now that the minimum intensity detectable by the human ear is , so . Lets replace those values in our equation to find :



Qe can conclude that since the explosion is under 100dB, it does not violates the regulation of the town. We used tow physical values to calculate the the intensity of the sound of the explosion, , and the minimum intensity detectable by the human ear .