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प्रश्न
Which of the following statements are correct?
- Sound is produced by vibrations.
- Sound requires a medium for propagation.
- Light and sound both require a medium for propagation.
- Sound travels slower than light.
विकल्प
i & ii only
i, ii & iii only
ii, iii & iv only
i, ii & iv only
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उत्तर
i, ii & iv only
Explanation:
Because light can travel in vacuum also but it is only sound that requires a medium to travel.
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संबंधित प्रश्न
Fill in the blank.
The number of times a body vibrates in one second is called its ______.
List four substances which are good absorbers of sound.
What is the difference between a compression and a rarefaction in a sound wave? Illustrate your answer with a sketch.
How is sound perceived by us?
The distance between three consecutive crests of wave is 60 cm. If the waves are produced at the rate of 180/ min, calculate:
- wavelength
- time period
- wave velocity.
Match the following.
| Ultrasonics | Frequency below 20Hz |
| Speed of sound in air | Needs material medium |
| Infrasonics | 330ms-1 |
| Sound propagation | Frequency more than 20000 Hz |
A musical instrument is producing continuous note. This note cannot be heard by a person having a normal hearing range. This note must then be passing through ______.
Name three animals, which can hear ultrasonic vibrations.
______ is an unwanted sound.
