We can begin by noting a few things:
• dB represents the sound intensity in decibels
• I represents intensity
• I0 represents reference intensity
Assuming the reference intensity (I0) is the base level of hearing represented by the equation 1 • 10^(-12) watts per meter^2, we can incorporate 100 into the equation.
If the sound intensity of rustling leaves (I) is 100 times the reference intensity (I0), we can set up an equation to solve:
I = 100 • 10^(-12)
Now to calculate the intensity of rustling leaves in decibels:
dB = 10 • log10(100 • (1 • 10^(-12)) / (1 • 10^(-12)))
dB = 10 • log10(100) = 10 • 2 = 20 dB
Therefore, the sound intensity of rustling leaves is 20 decibels.