Ear Damage from a Small Firecracker

[hotmail590]

Lets say there is a small firecracker that emits 1200 of peak power.
What is the peak intensity B in decibels at a distance of 1 m from the firecracker?


This is what i have tried:

B = 10log(I/Io)

I = 1200/pi Since I = power/area and the area is pir^2, pi(1m)^2

Io=( 10^-12 W/m^2)


So B= 10log([1200/pi] / [10^-12 ]) and i get around 135.83 , however the answer is incorrect


Can someone help please? THank you

[*melinda*]

Check the way you defined area for waves that propagate in space.

[hotmail590]

So the area is not a circle?

[*melinda*]

No, sound waves are spherical waves and travel in three dimensional space.