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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.
When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?
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.
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
Name three devices which work on the reflection of sound.
What is the other name of a loud-hailer ?
Fill in the blank with suitable word :
An echo is simply a ................... sound.
Why do we hear more clearly in a room with curtains than in a room without curtains ?
Why are the ceilings of concert halls made curved ? Draw a labelled diagram to illustrate your answer.
The echo of a sound is heard after 5 seconds. If the speed of sound in air be 342 m/s, calculate the distance of the reflecting surface.
Name any two objects which are good reflectors of sound.
What is the minimum distance in air required from a sound reflecting surface to hear an echo (at 20°C) ?
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 ?
Explain by giving a scientific reason.
We cannot hear the echo produced in a classroom.
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.
Answer the following question in your own words.
What should be the dimensions and the shape of classrooms so that no echo can be produced there?
State two conditions necessary for hearing an echo.
How can you calculate the speed of sound using 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.
Numerical problems:
An echo returned in 3s. What is the distance of the reflecting surface from the source given that the speed of sound is 330 ms-1?
