The question is incomplete. Here is the complete question.
To understand the decibel scale. The decibel scale is a logarithmic scale for measuring the sound intensity level. Because the decibel scale is logarithmic, it changes by an additive constant when the intensity when the intensity as measured in W/m² changes by a multiplicative factor. The number of decibels increase by 10 for a factor of 10 increase in intensity. The general formula for the sound intensity level, in decibels, corresponding to intensity I is
,
where 
is a reference intensity. for sound waves, is taken to be 
. Note that log refers to the logarithm to the base 10.
Part A: What is the sound intensity level β, in decibels, of a sound wave whose intensity is 10 times the reference intensity, i.e. 
? Express the sound intensity numerically to the nearest integer.
Part B: What is the sound intensity level β, in decibels, of a sound wave whose intensity is 100 times the reference intensity, i.e. 
? Express the sound intensity numerically to the nearest integer.
Part C: Calculate the change in decibels (
and 
) corresponding to f = 2, f = 4 and f = 8. Give your answer, separated by commas, to the nearest integer -- this will give an accuracy of 20%, which is good enough for sound.
Answer and Explanation: Using the formula for sound intensity level:
A)
β = 10
<u>The sound Intensity level with intensity 10x is </u><u>10dB</u>.
B)
β = 20
<u>With intensity 100x, level is </u><u>20dB</u>.
C) To calculate the change, take the f to be the factor of increase:
For 
:
β = 3
For 
:
β = 6
For :
β = 9
Change is
, = 3,6,9 dB
