what is the intensity of a sound at the pain level of 120dB? compare it to that of a whisper at 20dB?

Question

i keep getting an intensity level of -1 when the answer is 1. how do u get 1?

the formula is B1=10log(i1/i0)

Answer 1

I have no idea what the numbers "1" and "-1" are supposed to mean in this context. However, I do know that the decibel scale - like the richter scale - is logarithmic (as your formula makes clear): For each increase of 10 dB, the sound becomes 10 times louder.
30 dB is 10 times louder than 20dB
40dB is 10 times louder than 30dB
50dB is 10 times louder than 40dB

So 120dB is 10^10 times as loud as 20dB. That's 10,000,000,000 times louder.

No wonder it's painful.