Question

What do you understand by the term ultrasonic vibration? State 4 such vibrations?

Answer 1

HINT:Vibrations create sound waves, ultrasonic vibrations have frequency greater 20,000Hz these vibrations are inaudible to humans. Human range is 20Hz to 20,000Hz.

Complete step-by-step answer:
Ultrasonic vibrations are mechanical vibrations of the same type as sound waves but in a frequency range above that audible to the human ear. The lowest frequency in this range is often taken as 20 kilocycles per second (kcps), which corresponds to a wavelength of about 8 inches in solids, 2.4 inches in ordinary liquids and 0.63 inch in gases.

Four such vibrations are as under:
-Ultrasonic vibrations also have therapeutic applications, which can be highly beneficial when used with dosage precautions. Relatively high power ultrasound can break up stony deposits or tissue, accelerate the effect of drugs in a targeted area, and assist in the measurement of the elastic.

-Ultrasonic cleaners, sometimes mistakenly called supersonic cleaners, are used at frequencies from 20 to 40 kHz for jewelry, lenses and other optical parts, watches, dental instruments, surgical instruments, diving regulators and industrial parts. An ultrasonic cleaner works mostly by energy released from the collapse of millions of microscopic cavitation near the dirty surface. The bubbles made by cavitation collapse forming tiny jets directed at the surface.

-Ultrasonic vibrations has been studied as a basis for sonic weapons, for applications such as riot control, disorientation of attackers, up to lethal levels of sound.

-Ultrasonic vibrations signals have been used in "audio beacons" for cross-device tracking of Internet users.

Note:The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. The generally accepted standard hearing range for humans is 20 to 20,000 Hz. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in).