With the help of a diagram describe how compresion and rarefaction pulses are produced in air near a source of sound.

Explanation

1) Consider a vibrating membrane of a musical instrumentlike a drum or tabla.
2) As it moves back and forth, it produces a sound.
3) The figure shows the membrane at different instants and the condition of the air near it at those instants.
4) As the membrane moves forward, it pushes the particles of air in the layer in front of it.
5) So, the particles of air in the layer get closer to each other, hence the density increases.
6) This layer of air pushes and compresses the layer next to it and so on.
7) We call this disturbance as compression pulse.
8) When the membrane moves backward, it drags back the layer of air near it. Hence the density decreases.
9) The particles of air in the next layer on the right move into fill this less dense area.
10) This is a rarefaction pulse moves to right.
11) As the membrae moves back and forth repeatedly, compression and rarefaction pulses are produced, one after the other.
12) These two pulses travel one behind the other, carrying the disturbance with it.
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