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प्रश्न
What are ultrasonic waves ? Name two animals which can produce ultrasonic waves.
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उत्तर
Ultrasonic sound waves have frequencies higher than 20 kHz. It is inaudible as its frequency lies above the human audible range of frequencies (20 Hz–20 kHz). These sounds are produced by objects vibrating very rapidly. Bats and dolphins can produce these sounds.
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संबंधित प्रश्न
What is the audible range of the average human ear?
Name the organs of hearing in our body.
Can we hear (a) infrasonic waves (b) ultrasonic waves ?
What name is given to the sound waves of frequency too low for humans to hear ?
What is the difference between infrasonic waves and ultrasonic waves ?
What is the frequency range of hearing in humans ?
What are infrasonic waves ? Name two animals which produce infrasonic waves.
Three different vibrating objects produce three-types of sounds X, Y and Z. Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily. The sound X is used in hospitals to break kidney stones of a patient into fine grains which then get flushed out with urine. The sound Y is similar to that which is produced during an earthquake before the main shock wave is generated.
(a) What type of sounds are (i) X (ii) Y, and (iii) Z ?
(b) Name one device which can produce sound like X.
(c) Name one device in a science laboratory which can produce sound like Y.
(d) Name one device in our homes which can produce sound like Z.
(e) What is the frequency range of sounds like Z ?
One of the following can hear infrasound. This one is :
Which of the above two graphs (a) and (b) (Fig.12.3) representing the human voice is likely to be the male voice? Give a reason for your answer.

