Option B:
Solution:
Given sound level = 120 decibel
To find the intensity of a fire alarm:
where
Step 1: First divide the decibel level by 10.
120 ÷ 10 = 12
Step 2: Use that value in the exponent of the ratio with base 10.
Step 3: Use that power of twelve to find the intensity in Watts per square meter.
Now, do the cross multiplication,
Option B is the correct answer.
Hence .