Question

Describe with the help of a diagram, how compressions and rarefactions are produced in air near a source of sound.

Answer 1

Let us assume that a tuning fork is the source of sound.

1. When it vibrates and moves forward, it pushes and compresses the air in front of it, thus creating a region of high pressure. This region is called compression (C).
2. This compression moves forward away from the vibrating object, such as the tuning fork.
3. When the arm of the tuning fork vibrates back inwards (backwards), a low-pressure region is created, which is called rarefaction (R).
4. When an object vibrates this way, a series of compressions and rarefactions are created in the air. These compressions and rarefactions form sound waves, which propagate through the medium.