Question

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

Answer 1

Compression:

It is the region of the medium in which particles come to distances less than the normal distance between them.

Rarefaction:

It is the region of the medium in which particles of the medium get apart to distances greater than the normal distance between them.

Explanation:

1. When a tuning fork is set into vibrations, its prong compresses the air particles just in front of it. As a wave of compression progresses in the air along the horizontal, the particles of the air medium also execute periodic motion along the horizontal.

2. In a longitudinal wave if the particles of the medium vibrate along with the horizontal, then the disturbance also travels along the horizontal. Further, this wave travels in the form of compressions and rarefactions.

3. Wavelength is equal to the distance between the centers of two consecutive compressions or rarefactions.

4. The velocity of the longitudinal wave is given by:

$V=f\lambda$

Where $f$ is the frequency and $\lambda$ is the wavelength,