We know that human ear can not hear sounds of frequency less than 20Hz or more than about 20,000Hz. Sounds of frequency higher than 20,000Hz, which are inaudible to human ear, can be produced and are utilized in many useful ways. Such sounds are called ultrasonics.
It has been seen that ultrasonic waves carry more energy than audible sound waves. Moreover, according to the relation
, the wavelength of ultrasonic waves is very small. Due to these characteristics ultrasonics are usefully utilized in medical and technical fields
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For your information
The resources of oil and gas beneath the earth are searched by using ultrasonics. |
In medical field ultrasonic waves are being used to diagnose and treat different ailments. For diagnosis of different diseases ultrasonic waves are made to enter the huma body. These waves are reflected differently by different organs, tissues, benign or malignant tumors. The reflected ultrasonic waves are then amplified and fed to a monitor which forms an image of the internal organs of the body on its screen. Such an image helps in detecting the defects of these organs. Now a days, ultrasonic waves are used not only to find the sex of a baby but also to find its physical abnormalities before birth in the womb of the mother. Powerful ultrasonics are now being used to remove blood clots formed in the arteries.
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Do you know? Ultrasonic waves are used for the scaling of teeth as their vibrations are so intense that they remove easily the dirt and plaque sticking to the teeth. |
Due to excessive use, cracks appear in the interior of the moving parts of high speed heavy machines such as turbines engines of ships and aeroplanes. These cracks are not visible from outside but they can be very dangerous. Such cracks can be detected by ultrasonics. A powerful beam of ultrasonics is made to pass through these defective parts. While passing these waves are reflected by the surface of these cracks and flaws. The comparison of the ultrasonic waves reflected from the cracks and from the other surfaces of these parts can give a clue of the existence of the cracks.
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Interesting information The kidney stones can be crushed and removed out through urine with the help of ultrasonic waves without any surgery. |
The depth of an ocean can be measured by using ultrasonics. An ultrasonic pulse is sent down towards the ocean bed from the bottom of a ship. This pulse, after reflection from the ocean bed, reaches the ship where it is detected. The time taken by the ultrasonic pulse in travelling from the ship to the ocean bed and back to the ship is measured. Using this time and the speed of sound in water the depth of the ocean can be determined.
Germs and bacteria in liquids can be destroyed by using high intensity ultrasonic waves.
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Do you know?
The depth of an ocean can be is measured by using ultrasonics. |
