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प्रश्न
What is ultrasound ? What is the difference between ordinary sound and ultrasound ?
उत्तर
Ultrasound waves are high-frequency sound waves. Due to higher frequency, they can penetrate into matter to a large extent.
We can differentiate between ordinary and ultrasonic waves as :
| Audible sound waves | Ultrasound waves |
| They have a frequency range of 20 Hz–20,000 Hz | They have frequencies above 20,000 Hz |
| These sounds are audible to human ears. | These sounds are inaudible to human ears. |
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संबंधित प्रश्न
Name the organs of hearing in our body.
Can we hear (a) infrasonic waves (b) ultrasonic waves ?
What type of sound waves are produced by a vibrating simple pendulum ?
What is the difference between infrasonic waves and ultrasonic waves ?
What is the frequency range of hearing in humans ?
Which of the following sound frequencies cannot be heard by a human ear ?
(i) 10 Hz
(ii) 100 Hz
(iii) 10,000 Hz
(iv) 15 Hz
(v) 40,000 Hz
The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 ms–1)
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 ?
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.
For hearing the loudest ticking sound heard by the ear, find the angle x in Fig.12.4.
