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प्रश्न
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उत्तर
Bats make a series of twittering sound, so high pitched that human ear can not hear. These sound waves strike against the obstacles less in their path of flight and send back echoes to the bat’s ear. The echoes tell the bats, how they must turn in the air to avoid colliding with the obstacles or with one another.
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संबंधित प्रश्न
How are the wavelength and frequency of a sound wave related to its speed?
Write true or false for a given statement.
Larger is the amplitude, feeble is the sound.
Write true or false for a given statement.
A ticking clock sound is heard late when heard through a metal.
What is the nature of sound waves in air?
The flash of a gun is seen by a man 3 seconds before the sound is heard. Calculate the distance of the gun from the man (Speed of sound in air is 332 m/s).
Complete the following sentence :
Sound is produced by a ___________ body.
A cannon is fired at A (see diagram). An observer at B hears two sounds. The first sound is heard after 1 second and the second 3s after the observer sees the flash. (Velocity of sound = 340 ms−1)
(i) Why does the observer see the flash before he hears the sound?
(ii) Calculate the distance x between the observer and the wall.
Match the pairs.
| Group ‘A’ | Group ‘B’ |
| (a) Flute | (1) Frequency less than 20 Hz |
| (b) Frequency | (2) Frequency more than 20000 Hz |
| (c) Sound level | (3) Vibrations in the air |
| (d) Ultrasonic sound | (4) Measured in Hz |
| (e) Infrasonic sound | (5) Decibel |
A continuous progressive transverse wave of frequency 8 Hz moves across the surface of a ripple tank
With reference to the frequency, describe the movement of water on the surface
What do you mean by the frequency of sound?
Sound waves travel very fast in
Sound can travel through solids, gases, liquids, and even vacuum.
Name three animals, which can hear ultrasonic vibrations.
The speed of sound in air at 0°C is ______.
What is a wave?
Find the odd one out.
