(measured in 
), its intensity level is given by
is: a unit of (acoustic) intensity level. [P5.7]
permits representation: of intensity level in terms of a reference intensity level:
given a sound of intensity (measured in ), its intensity level is given by
where 
Audible, non-painful sounds usually have intensity levels in the range 0 to 120 dB. [P5.7]
Copyright 1997, The Open University