1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Decibels and intensity

  1. Nov 18, 2008 #1
    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. jcsd
  3. Nov 19, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    That's right.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook