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Write the definition of Echo.

Important Questions on Sound

EASY
Science>Physics>Sound>Reflection of Sound
A man standing in front of a vertical cliff fires a gun. He hears the echo after 3.5 sec. On moving closer to the cliff by 84 m, he hears the echo after 3 sec. Calculate the distance of the cliff from the initial position of the man.
EASY
Science>Physics>Sound>Reflection of Sound
A girl drops a ball from a height h=20 m. It strikes the ground elastically and returns to her hand. An echo of the thud of the ball striking the ground is produced from a nearby cliff. The echo is head at exactly the same moment when the ball returns to the girl's hand. (Take g = 10 ms-2  and vsound=350 ms-1). The distance of the cliff from the girls is close to:
EASY
Science>Physics>Sound>Reflection of Sound

A person clapped his hands near a cliff and heard the echo after 4 s. The distance between the cliff and the person will be :

(Speed of sound is 346 m s-1) 

EASY
Science>Physics>Sound>Reflection of Sound
Sound travels at a speed of 1450 ms-1through water. A submarine detects objects around it by sending sound waves and detecting echo (reflected sound) heard after 4 s. Then the object must be at a distance of:
EASY
Science>Physics>Sound>Reflection of Sound
What is the difference between reverberation and echo?
MEDIUM
Science>Physics>Sound>Reflection of Sound
Name the system which enables us to locate underwater objects by transmitting ultrasonic waves and detecting the reflecting impulse.
EASY
Science>Physics>Sound>Reflection of Sound
If the velocity of sound in air is 340 m s-1 and x is the minimum distance between sound source and reflecting surface to get echo from general sound, then :
EASY
Science>Physics>Sound>Reflection of Sound
What is the minimum distance required to hear an echo in air?
EASY
Science>Physics>Sound>Reflection of Sound
Sound signal from a ship floating in water hits the bottom of the sea and reflects back to the ship after 6 s. Speed of sound in water is 1500 m s-1. Calculate the depth of the sea.
EASY
Science>Physics>Sound>Reflection of Sound
A man who is standing at a distance of 850 m from a sound reflecting surface claps loudly. If the velocity of the sound in air is 340 ms-1 then the time taken by the echo to reach him is
HARD
Science>Physics>Sound>Reflection of Sound
A pendulum  has a frequency of 4 vibrations per second. An observer starts the pendulum and fires a gun simultaneously. He hears the echo from the cliff after 6 vibrations of the pendulum. If the velocity of sound in air is 340 ms-1, find the distance between the cliff and the observer. 
EASY
Science>Physics>Sound>Reflection of Sound
Name a place where you can experience echo.
EASY
Science>Physics>Sound>Reflection of Sound
What are the conditions necessary for the formation of an echo?
EASY
Science>Physics>Sound>Reflection of Sound
How long does sound persist in our ears?
EASY
Science>Physics>Sound>Reflection of Sound
For doing the experiment on the verification of laws of reflection of sound,
EASY
Science>Physics>Sound>Reflection of Sound
Why do we not hear echo at all places?
EASY
Science>Physics>Sound>Reflection of Sound
What is meant by reflection of sound?
MEDIUM
Science>Physics>Sound>Reflection of Sound
What is meant by an echo? How is it heard? Explain the various conditions necessary for the formation of echoes.
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Science>Physics>Sound>Reflection of Sound

While doing an experiment on verifying the laws of reflection of sound, four students measured the angles ∠i and ∠r as shown in the diagram below. The correct measurement of the angles of incidence and angles of reflection has been done by which student?

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MEDIUM
Science>Physics>Sound>Reflection of Sound

What is an echo? Explain how the principle of echo is used by

a. bat during its flight at night and

b. a dolphin to locate small fishes as its prey.