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प्रश्न
Fill in the blank with suitable word :
Echoes are caused by the ...................... of sound.
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उत्तर
Echoes are caused by the reflection of sound.
संबंधित प्रश्न
An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s−1?
The minimum distance between the source and the reflector in air. So that an echo is heard is approximately equal to ______.
Explain why, the flash of lightning reaches us first and the sound of thunder is heard a little later.
Which of the following statement best describes frequency?
Name three devices which work on the reflection of sound.
Name the device which is used to address a small gathering of people.
On which day, a hot day or a cold day, an echo is heard sooner ? Give reason for your answer.
Why are the ceilings of concert halls made curved ? Draw a labelled diagram to illustrate your answer.
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 ?
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 an echo ? How is echo formed ?
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 bare room
______ allows bats to navigate through dark caves and find insects for food.
______ is an image obtained by the use of reflected ultrasonic waves.
Assertion: The sound which we hear again is called Echo.
Reason: The sensation of sound (Echo) persists in our brain for about 1 s.
