Question

Taking the example of a tuning fork, explain how a vibrating body produces longitudinal waves in the air.

Answer 1

1. Longitudinal waves are waves in which the vibration of the medium is parallel to the direction the wave travels and the displacement of the medium is in the same direction of the wave propagation.
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4. A fork consists of a handle and two tines. When the tuning fork is hit with something hard (eg. a rubber hammer), the tines begin to vibrate.
5. As the tine moves outward from its normal position, it compresses the surrounding air molecules which creates a high-pressure region (compression).
6. As the tine moves inward from its normal position, the air surrounding the tine expands; this produces a low-pressure region (rarefaction).
7. As the tines continue to vibrate, alternating compression and rarefaction are created, carrying the longitudinal sound waves from one place to another.