Advertisements
Advertisements
Question
What are infrasonic waves ? Name two animals which produce infrasonic waves.
Solution
Infrasonic sound waves have frequencies lesser than 20 Hz. It is inaudible as its frequency lies below the human audible range of frequencies (20 Hz–20 kHz). These sounds are produced by objects vibrating very slowly. Whales and elephants can produce these sounds.
APPEARS IN
RELATED QUESTIONS
What is the audible range of the average human ear?
What is the range of frequencies associated with ultrasound?
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.
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 type of sound waves are produced by a vibrating simple pendulum ?
What is the difference between infrasonic waves and ultrasonic waves ?
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
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 ?
