An increase in sound level of 20 dB represents an increase in intensity (W/m2 ) of:

D: If the sound level difference between two sounds whose intensities are I1 and I2 is 20 dB, 20 10 2 1 = ×      log  I I , so a sound level of 20 dB means that the log term must be 2. Now the log(100) = 2, hence I2/I1 = 100. Thus one sound is 100 times the intensity of the other.