Confused

[airbornewife29]

I worked this problem and got the right answer, but my teacher says I skipped a couple of steps between these two:
96 = 10 Log(I/10^-12)
-2.4 = LogI
Can anyone help me. For the life of me, I can't figure out what steps I skipped. I am soooo lost!!!!

Problem:
City ordinanaces. In Albuquerque, New Mexico , The maximum allowable sound level from a car's exhaust is 96 db. What is the intensity of such a sound?
L = 10 Log (I/Io)
96 = 10 Log(I/10^-12)
-2.4 = LogI
10^-2.4 = I
0.00398 = I

 

[mmm4444bot]

teacher says I skipped a couple of steps between these two:

96 = 10 Log(I/10^-12)

-2.4 = Log(I)

Teacher probably wants to see how you extracted 10^(-12) from the Log's input of I/10^(-12), to wind up with Log(I).

How did you do it?

One way is to use this property:

log(a/b) = log(a) - log(b)

Log(I/10^[-12])

Log(I) - Log(10^[-12])

Log(I) + 12 Log(10)