The Decibel scale
The amount you could be expected to know is limited. There are some readings below but the key ideas are
β = 10 log (I/I0)
where I = Intensity and I 0 = The Threshold of human hearing [1 x 10-12 Wm-2]
You should be familiar with some common levels (loud, quiet and painful) but these should be easy to fine/make a note of.
A
pretty straightforward description
There
is probably too much information here but worth a look: