If the distance between the source of sound and observer is reduced to one half, then the intensity of sound will become

Let the power delivered by the sound wave be 'P'

Intensity by definition is the power delivered per unit area.

i.e. I =

dA

dP

;

In spherical polar coordinate system dA = r

2

Ω

I =

r

2

Ω

dP

;

I ∝

r

2

1

So if distance increases 3 fold. The Intensity becomes

9

1

times the initial

insects!

explanation:

f=ma newton

f=100x2.5=250n