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प्रश्न
How do bats avoid obstacles in their way, when in flight?
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उत्तर
Bats can produce and detect the sound of very high frequency up to about 1000kHz. The sounds produced by flying bats get reflected back from any obstacle in front of it. By hearing the echoes, bats come to know even in the dark where the obstacles are. So they can fly safely without colliding with the obstacles.
संबंधित प्रश्न
The human ear can detect continuous sounds in the frequency range from 20 Hz to 20,000 Hz. Assuming that the speed of sound in air is 330 ms1 for all frequencies; calculate the wavelengths corresponding to the given extreme frequencies of the audible range
State two factors on which the speed of a wave travelling in a medium depends.
What adjustments would you make for tuning a stringed instrument for it to emit a note of a desired frequency?
The following diagram shows three ways in which the string of an instrument can vibrate.
(a) which of the diagram shows the principal note?
(b) which has the frequency four times that of the first?
(c) what is the ratio of the frequency of the vibration in (i) and (ii)?
Name the principle on which a soundboard works.
Why will an echo not be heard when the distance between the source of the sound and the reflecting surface is 10 m?
In what respect does waveforms of noise and a musical note differ. Draw diagrams to illustrate your answer.
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.
