EASY
Earn 100

The persistence of hearing for human beings is not more than

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Important Questions on Sound

EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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.
HARD
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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. 
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Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
What is the difference between reverberation and echo?
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Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
What is the minimum distance required to hear an echo in air?
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
The acronym ‘SONAR’ stands for
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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.
MEDIUM
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Name the system which enables us to locate underwater objects by transmitting ultrasonic waves and detecting the reflecting impulse.
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics

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
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Which of the following animal produce ultrasound?
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
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
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Narrow metal tubes, well polished from inside, are used in this experiment. The tubes should be narrow in order to make sound waves
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
For verifying the laws of reflection of sound experimentally, the reflecting surface (screen) used should be
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Which of the following is not based on reflection of sound?
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
While performing an experiment on verifying laws of reflection of sound, a student is to choose from (i) a narrow or a wide tube, and (ii) a strong or a faint source of sound.
The observed experimental difference, between the values of angle of incidence and angle of reflection, is likely to be minimum when he chooses a
EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Ultrasonic waves are made to reflect from various parts of the heart and form the image of the heart. This technique is called ____________________.
MEDIUM
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics

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?

Question ImageQuestion ImageQuestion ImageQuestion Image

EASY
Physics>Waves and Oscillations>Sound>Echo, Reverberation and Acoustics
Sound whose frequency is below 20 Hz is called _____.