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प्रश्न
Answer the following question in your own words.
What factors are important to get a distinct echo?
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उत्तर
- Ambient temperature and the distance between the sound source and the reflecting surface are two factors that are important in the formation of echoes.
- The speed of sound in air at 22°C is 344 m/s. Our brain retains a sound for 0.1 seconds, so only if the sound reaches the barrier and reaches the listener's ears after more than 0.1 seconds will we hear it as a separate sound.
- Distance = Speed × Time
= 344 m/sec × 0.1 sec
= 34.4 m
Thus, the distance from the source of the sound to the obstacle and back to the source is the distance that the sound must travel at least 34.4 m. - So the minimum distance from the sound source to the obstacle should be half of the above distance i.e. 17.2 meters to hear a clear echo.
- These distances are different at different temperatures.
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संबंधित प्रश्न
Does sound follow the same laws of reflection as light does? Explain.
What is meant by an echo?
A man is standing at a distance of 12 m from a cliff. Will he be able to hear a clear echo of his sound? Give a reason for your answer.
Which property of sound leads of the formation of echoes ?
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Fill in the blank with suitable word :
An echo is simply a ................... sound.
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
Why are the ceilings of concert halls made curved ? Draw a labelled diagram to illustrate your answer.
The speed of sound in water is 1500 metres per second. How far away from an under-sea rock should a deep sea diver be so that he can hear his own echo ?
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a furnished room
An echo-sounder in a trawler (fishing boat) receives an echo from a shoal of fish 0.4 s after it was sent. If the speed of sound in water is 1500 m/s, how deep is the shoal ?
Answer the following question in your own words.
Study the construction of the Golghumat at Vijapur and discuss the reasons for the multiple echoes produced there.
What is the minimum distance needed for an echo?
A man is standing between two vertical walls 680 m apart. He claps his hands and hears two distinct echoes after 0.9 seconds and 1.1 seconds respectively. What is the speed of sound in the air?
State two conditions necessary for hearing an echo.
What are the medical applications of echo?
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
Rohan conducted experiments on echo in different media. He observed that a minimum distance of 'x' meters is required for the echo to be heard in oxygen and 'y' meters in benzene. Compare 'x' and 'y'. Justify your answer.
Speed of sound in oxygen: 340 ms-1
Speed of sound in benzene: 200 ms-1
