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प्रश्न
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.
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उत्तर
We have to calculate time taken by the sound wave to reach the reflecting surface.
Given: Distance between the observer and reflecting surface d = 825 m
Velocity of sound ν = 330 m/s
We know the time taken by sound wave to reach the reflecting surface is,
t = 2d/ν
⇒ t = (2)(825)/330
⇒ t = 5 s
This is the required time.
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संबंधित प्रश्न
What is meant by an echo?
Name the device which is used to address a small gathering of people.
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.
Name any two objects which are good reflectors of sound.
Answer the following question in your own words.
What is an echo?
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?
What is the minimum distance needed for an echo?
When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer.
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?
