Sound intensity using decibel values

[123helpme]

okay so I am having trouble with my sound ISU (independent study unit). Though my teacher said he would help, when i asked he said he cant...

what i need to find is the sound intensity for the following decibel values..
a) 100dB
b) 55dB

now the only relevant equation would be \beta= 10 log (I_{}2/I_{}1)
and I_{}1=1.0x10^-12 W/m^2

i have attempted multiple times but can't seem to come to the correct answer
the textbook gave the answers but no solution
a)0.10 W/m^2
b) 3.2x10^-7 W/m^2

a) what i tried was subsituting \beta for 100dB and I_{}1=1.0x10^-12 W/m^2
but from there I am not quite sure what to do

help me please!

 

[KLoux]

You'll need to post more details. What answers are you getting? What did you try? Show step-by-step. Also, check that you copied the book answer correctly for (a).

-Kerry

 

[Redbelly98]

Welcome to Physics Forums.

a) what i tried was subsituting \beta for 100dB and I_{}1=1.0x10^-12 W/m^2
but from there I am not quite sure what to do

help me please!

You're on the right track. Can you post the equation you get when you make that substitution? You are trying to find I₂ in the equation.