The intensity of a 80-dB whistle is doubled. What is the new decibel level?

Question

Quizplus · Accepted Answer

The formula to calculate the change in decibel level is:

ΔdB = 10 log (I2/I1)

Where I1 is the initial intensity and I2 is the final intensity.

Since the intensity has doubled, I2 is twice I1:

ΔdB = 10 log (2I1/I1) = 10 log 2 = 3.01 dB

So the new decibel level is 80 dB + 3.01 dB = 83.01 dB, which we can round to 83 dB.

Therefore, our answer is choice C.

The Intensity of a 80-DB Whistle Is Doubled