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11. Sound eLearn.Punjab

• In medical field, ultrasonic waves are used to diagnose and treat different ailments. For diagnosis

of different diseases, ultrasonic waves are made to enter the human body through transmitters.

These waves are reflected differently by different organs,

tissues or tumors etc. The reflected waves are then

amplified to form an image of the internal organs of the

body on the screen (Fig.11.13). Such an image helps in

detecting the defects in these organs.

• Powerful ultrasound is now being used to remove blood

clots formed in the arteries.

• Ultrasound can also be used to get the pictures of thyroid

gland for diagnosis purposes. Fig. 11.13 : Doctors are taking
• Ultrasound is used to locate underwater depths or is ultrasound test of a patient with an

used for locating objects lying deep on the ocean floor, ultrasound machine.

etc. The technique is

called SONAR, (sound navigation and ranging). The sound

waves are sent from a transmitter, and a receiver collects

the reflected sound (Fig.11.14). The time-lapse is calculated,

knowing the speed of sound in water, the distance of the

object from the ocean surface can be estimated.

• SONAR ranging is also used to see the shape and the size of

the object. Cracks appear in the interior of moving parts of high

Fig. 11.14: Ultrasonics are used to speed heavy machines
measure the depth of water by echo such as turbines, engines
of ships and airplanes
method.

due to excessive use.

These cracks are not visible from outside but they can be

very dangerous. Such cracks can be detected by ultrasonic. A

powerful beam of ultrasound 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 cracks and from the surfaces

of these parts can give a clue of the existence of the cracks.

• Germs and bacteria in liquids can also be destroyed by using

high intensity ultrasonic waves.

Animation 11.8: Ultrasonis testeing
Source & Credit: ndt-ed

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