The pressure amplitude in a sound wve from a radio receiver is `2.0xx10^-2 Nm^-2` an the intensity at a point is `5.0xx10^-7Wm^-2.` If by turning the volume knob the pressure amplitude in increased to `2.5xx10^-2Nm^-2` evaluate intensity.

Explanation

As intensity is proportional to square of pressure amplitude.
`:. (I_(2))/(I_(1))=((p_(2))/(p_(1)))^(2)`
`(I_(2))/(5xx10^(-7))=((2.5xx10^(-2))/(2xx10^(-2)))^(2)=(25)/(16)`
`I_(2)=(25)/(16)xx5xx10^(-7)=7.8xx10^(-7)W//m^(2)`