Question 1189073
D=10 log (I/Io)
12.5= log (I/io)
raise to 10th power
3.16x 10^12=I/Io
Io=10^-12
so I=3.16 w/m^2
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For the second part, the intensity of a whisper is about 10^-10 decibels, 9 orders of magnitude higher than what is given, and if 10^-19 is used, the answer will be negative.