Question

(a) Explain the differences and similarities among the concepts of intensity,

sound level, and power. (b) What happens to intensity as the source of sound

moves closer to the observer? (c) What happens to sound level? And (d) what

happens to power?

Answer 1

(A) Power is the rate at which sound energy is emmitted by source.
  
P unit = W

Intenisty is the energy that reahces at a point per unit area.

I unit = W/m^2

This is logarthmic scale defined to measure sound intensity from a reference sound intensity Io.

Or more precisely, it is the measurment of loudness of sound.

(b) as source moves closer to the observer, Intensity increases.

I is propotional to 1 /r^2 .

(C) sond level = 10 log(I / Io)

as intensity increase so sound level also increases.

(D) source of power is constant. It is independent of distance.