Posted by emily on .
A radio set at a sound level of 20 dB is suddenly increased to 80 dB. how many more time greater is the pressure amplitude at 80 dB? I do not know what to do please help

Physics 
Henry,
20Log(Vo/Vi) = 20db,
Log(Vo/Vi) = 1,
Vo/Vi = 10^1 = 10. = Voltage ratio.
20Log(Vo/Vi) = 80db,
Log(Vo/Vi) = 4,
Vo/Vi = 10^4 = 10,000.
Ratio = 10^4 / 10^1 = 10^3 = 1,000.
Therefore, the signal level at 80db is
1,000 times the signal level at 20db.