# Decibels and intensity

1. Nov 18, 2008

### Alicek

1. The problem statement, all variables and given/known data
if two firecrackers produce a sound level of 95 dB when fired simultaneously at a certain place, what will the sound level be if only one is exploded?

2. Relevant equations

dB=10 LOG I + 120

3. The attempt at a solution
would I use 2I instead of I making an equation like 95 = 10 log 2I + 120 and then solve for one I?
Or set up the usual equation and then once I solve for I just divide it in half?
Also, I know that when intensity doubles, it goes up by 3 decibels, so do I just assume that two firecrackers is double the intensity of 1 and just subtract 3 decibels from the original 95?

2. Nov 19, 2008

### Redbelly98

Staff Emeritus
That's right.