The loudness level of a sound,D,in decibels, is given by the formula

D=

10log(10^12I),whereIis the intensity of the sound, in watts per meter².Decibel levels range from 0, a barely audible sound, to 160, a sound resulting in a ruptured eardrum. (Any exposure to sounds of 130 decibels or higher puts a person at immediate risk for hearing damage.) What is the decibel level of a normal conversation, 3.2 x 10^-6 watt per meter²?