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(3 X 3 = 9) CASE STUDY QUESTION 26. Ultrasounds can be used to detect cracks and flaws in metal blocks. Metallic components that are generally used in construction of big structures like buildings, machines and also scientific equipment. The cracks or holes inside metal blocks, which are invisible from outside, reduce the strength of the structure. Ultrasonic waves are allowed to pass through the metal block and detectors are used to detect the transmitted waves. If there is even a small defect, the ultrasound gets reflected back indicating the presence of flaw or defect. Clearly indicated in the figure Defect or flaw Ultrasound Detectors Metal Block (a) The transmitter sends an ultrasound wave of speed 5960m/s through a long steel bridge and a block reflects it back after 0.02s. how far the block in the metal bridge is from the transmitter. (b) With the above property of ultrasound waves, Can ultrasonic waves be used in the medical field? If so, how and give one use in the medical field to justify your answer? (c) Give two practical applications of reflection of sound waves?
Asked by mailtoparvathyprajith | 31 Jan, 2024, 06:55: PM

(a) Speed of sound, v = 5960 m/s

time taken to reflect, t = 0.02 s

Distance = (speed x time/2)

distance = 5960 x 0.02/ 2 = 59.2 m ≈ 59 m

Thus, the block is 59 m away from the transmitter.

(b) Application of ultrasound in medical field:

Medical application

(1) Ultrasound Imaging:- Ultrasounds are used to get images of muscles, blood vessels and organs of human body.

(2) therapeutic applications:- a non-invasive therapy for musculoskeletal disorders and cancer treatment.

(c) Two practical applications of reflection of sound waves:

(i) Hearing aid: It is a device used by people who are hard of hearing. Here the sound waves, which are received by the hearing aid are reflected into a narrower area leading to the ear.

(ii) Soundboards: Curved surfaces can reflect sound waves. This reflection of sound waves is used in the auditorium to spread the waves uniformly throughout the hall. Reflection of sound waves is done by using Sound Boards. The speaker is located at the focus of the soundboard.

Answered by Shiwani Sawant | 02 Feb, 2024, 04:16: PM

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