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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
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?
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.
Name three devices which work on the reflection of sound.
What is the other name of a loud-hailer ?
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
In which medium, air or water, an echo is heard much sooner ? Why ?
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 ?
Name any two objects which are good reflectors of sound.
State the laws of reflection of sound.
A man standing 825 metres away from a cliff (steep rock) fires a gun. After how long will he hear its echo ? Speed of sound in air is 330 m/s.
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a furnished room
The frequencies of four sound waves are given below. Which of these sound waves can be used to measure the depth of sea by the echo method ?
Explain by giving a scientific reason.
We cannot hear the echo produced in a classroom.
Answer the following question in your own words.
What is an echo?
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?
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?
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
