Question

Spherical sound waves are emitted uniformly in all directions from a point source. The variation in sound level SL as a function of distance ‘r’ from the source can be written as
Where a and b are positive constants.

• A. $SL=-blog{r}^a$
• B. $SL=a-b(logr{)}^2$
• C. $SL=a-blogr$
• D. $SL=\frac{a-b}{r^2}$

Answer 1

The correct option is C $SL=a-blogr$

$SL=10Log\frac{I}{I_0}$
$=10log\frac{k}{I_0{r}^2}$
$=10logK-10log\left(I_0{r}^2\right)$
$=10logk-10log{I}_0-20logr$
= a – b log r