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प्रश्न
Answer the following question in your own words.
What is an echo?
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उत्तर
An echo is the reflection of sound waves off a surface, such as a wall, mountain, or building, that returns to the listener after a delay. It occurs when the reflected sound reaches the ear after at least 0.1 seconds, allowing the listener to distinguish it from the original sound. Echoes are commonly experienced in large, empty spaces or near hard, smooth surfaces.
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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 the device which is used to address a small gathering of people.
In which medium, air or water, an echo is heard much sooner ? Why ?
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.
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.
A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a bare 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?
What are the medical applications of echo?
______ is an image obtained by the use of reflected ultrasonic waves.
What is an echo? Write the conditions to hear an echo.
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?
Answer the following question in your own words.
What factors are important to get a distinct echo?
