16. Sound

Sound waves

Sound is a form of energy which travel as waves. Sound waves are produced by objects that vibrate in a medium. The medium can be a gas, liquid or solid. A vibrating object produces sound waves by the shifting layers of air particles. The vibrating object pushes and...

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Ultrasound

Sound waves with frequencies above 20 kHz are called ultrasound, which exceeds the audible range for humans. Application In medical : Ultrasound is used to observe the internal parts of the body, especially in the development of a foetus. Ultrasound pulses are emitted...

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