In the following statements, tick ‘T’ against those which are true, and ‘F’ against those which are false.- Sound cannot travel in vacuum. (T/F)
- The number of oscillations per second of a vibrating object is called its time period. (T/F)
- If the amplitude of vibration is large, sound is feeble. (T/F)
- For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
- The lower the frequency of vibration, the higher is the pitch. (T/F)
- Unwanted or unpleasant sound is termed as music. (T/F)
- Noise pollution may cause partial hearing impairment. (T/F)
- Sound cannot travel in vacuum. (T/F)
- The number of oscillations per second of a vibrating object is called its time period. (T/F)
- If the amplitude of vibration is large, sound is feeble. (T/F)
- For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
- The lower the frequency of vibration, the higher is the pitch. (T/F)
- Unwanted or unpleasant sound is termed as music. (T/F)
- Noise pollution may cause partial hearing impairment. (T/F)
Solution and Explanation
(a) Sound cannot travel in vacuum. (True)
(b) The number of oscillations per second of a vibrating object is called its time period. (False)
(c) If the amplitude of vibration is large, sound is feeble. (False)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (True)
(e) The lower the frequency of vibration, the higher is the pitch. (False)
(f) Unwanted or unpleasant sound is termed as music. (False)
(g) Noise pollution may cause partial hearing impairment. (True)
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Concepts Used:
Sound
Sound is a vibration that propagates the mechanical wave of displacement and pressure, through a medium can be of any matter. In other words, the sound is the thin line between Music sound and Noise.
Types of Sounds:
Sound can be divided into two types depending on its frequency. The following are:-
Infrasonic Waves:
- Infrasonic waves have a frequency lower than 20 Hz. Since it is below the human hearing range, it is inaudible to humans.
- However, several other living organisms use these waves to communicate, whales, sharks, elephants, hippopotamus, etc. these waves are also used in the scientific field, it is used to study upcoming earthquakes, volcanic eruptions, human heart rates, rock formation stages, etc.
Ultrasonic waves:
- Ultrasonic waves have a frequency higher than 20 kHz. Since it is above the human hearing range, it is inaudible to humans.
- These waves are used in the scientific field, it is used to study human heart rates, to take sonograms, navigation of directions, imaging things, uniform sample mixing, communication, testing of samples, etc.