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Ultrasound is the sound with frequencies higher than 20,000 hertz.
Use of ultrasound
- Ultrasound is used to clean street lights by immersing the lighting unit in a tank of water and using ultrasonic waves to dislodge the dust particles from the surface of the unit. It is also used to clean jewelry and intricate mechanical and electronic components and weld plastics.
- Other application of ultrasound is in quality control of metals and meat. Ultrasound is used to detect the position of flaws in metal and in determining the thickness of lean and fat meat in livestock while the animals are still alive.
- Ultrasound is used to form images of babies in the womb (prenatal scanning). High frequency ultrasound, typically 3.5 million Hz, is sent into the body and is partially reflected as it encounters different types of tissue. These reflections are used to form an image on a television monitor. Ultrasound is also used to provide images of the heart, liver, kidneys, gal bladder, breast, eye, and major blood vessels.
- In hospitals, ultrasonic power is used to pulverise kidney stones, thus avoiding the need for surgical removal.
- Automatic focusing cameras use ultrasonic echo-location to determine the distance being photographed.
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