A baby cries on seeing a dog and the cry is detected at a distance of 3.0 m such that the intensity of sound at this distance is `10^(-2) W m^(-2)` . Calculate the intensity of the baby's cry at a distance 6.0 m

Explanation

`I_(1)` is the intensity of sound detected at a distance 3.0 m and it is given as `10^(-2) W m^(-2) `. Let `I_(2)` be the intensity of sound detected at a distance 6.0 m . Then `r_(1) = 3.0 m , r_(2) = 6.0` m
and since `I prop (1)/(r^(2))`
the power output does not depend on the observer and depends on the baby . therefore ,
`(I_(1))/(I_(2)) = (r_(2)^(2))/(r_(1)^(2)) implies I_(2) = I_(1) (r_(1)^(2))/(r_(2)^(2))`
`I_(2) = 0.25 xx 10^(-2) W m^(-2)`