Question

Could someone explain how the attenuation of sound or light through an absorber is an example of exponential decay?

Answer 1

Okay, so say you have something that looks like this

As light, or sound doesn't matter, bounces around in there a little of it will be absorbed, attenuated, each time it hits one of the wall of the cube. So, as it bounces around the box it will lose some amplitude, say half, each time it hits one of the walls. So if its original amplitude is A then after the first hit it will be A/2, then A/4, then A/6, so its decay is given by A(1/2)^n and thus, it decays exponentially as it bounces around the box.