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प्रश्न
What is the range of frequencies associated with ultrasound?
उत्तर
Frequencies higher than 20 kHz are called ultrasonic sound or ultrasound.
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संबंधित प्रश्न
What is the audible range of the average human ear?
A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 m s−1.
Fill in the blanks with suitable words.
A sound wave consists of places of higher pressure called ................. and places of................pressure called.................
Choose the infrasonic waves and ultrasonic waves from the following frequencies :
(i) 10,000 Hz
(ii) 30,000 Hz
(iii) 18 Hz
(iv) 50,000 Hz
(v) 10 Hz
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
What is ultrasound ? What is the difference between ordinary sound and ultrasound ?
What are ultrasonic waves ? Name two animals which can produce ultrasonic waves.
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 ?
A girl is sitting in the middle of a park of dimension 12 m × 12 m. On the left side of it, there is a building adjoining the park and on the right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.
