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प्रश्न
How are bats able to fly in the dark?
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उत्तर
Sound waves of frequency higher than 20,000 hertz are not audible to human ears. Those are known as ultrasonics. Let us explain how bats can avoid obstacles while flying in complete darkness. During the flight in complete darkness, a bat produces ultrasound in a series of impulses. The impulses on reflection from the obstacle under observation are received by the animal. The animal interprets the distance of the obstacle from the time interval between the transmission and reception of the impulses. The phase difference between the echoes received by the ears enables the animal to locate the exact position of the obstacle.
संबंधित प्रश्न
Define frequency term in relation to a wave.
What is the condition necessary for an echo to be heard distinctly?
What adjustments would you make for tuning a stringed instrument for it to emit a note of a desired frequency?
What is the shape of a soundboard kept behind the speaker on the stage of a big hall ?
Define the term Frequency (as applied to sound waves)
Waves produced on the surface of the water are formed to move with a velocity of 24 ms−1. If the wavelength of these waves equals 20 cm. find the
(i) frequency (no. of waves produced per second)
(ii) the time period (i.e. the time required to produce one wave) for these waves.
(i) A man stands at a distance of 68 m from a cliff and fires a gun. After what time interval will he hear the echo, if the speed of sound in air is 340 ms−1?
(ii) If the man had been standing at a distance of 12 m from the cliff would he have heard a clear echo?
A sound wave whose frequency is 5000 Hz travels in air and then hits the water surface. The ratio of its wavelengths in water and air is ______.
The direction of the incident sound, the direction of reflected sound, and the normal are in different Planes.
