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प्रश्न
What is an echo ? How is echo formed ?
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उत्तर
The repetition of sound caused by the reflection of sound is called echo. An echo is produced when sound is reflected from a hard surface such as a tall brick wall or a cliff.
संबंधित प्रश्न
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.
Fill in the blank with suitable word :
An echo is simply a ................... sound.
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.
What is meant by 'reflection of sound' ? What type of surfaces are the best for reflecting sound ?
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) ?
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 ?
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?
How can you calculate the speed of sound using echo?
______ allows bats to navigate through dark caves and find insects for food.
______ is an image obtained by the use of reflected ultrasonic waves.
