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प्रश्न
State the use of echo by a bat, dolphin and fisherman.
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उत्तर
Bats, dolphin and fisherman detect their enemies or obstacles or position of fish by emitting/sending the ultrasonic waves and hearing/detecting the echo.
संबंधित प्रश्न
What adjustments would you make for tuning a stringed instrument for it to emit a note of a desired frequency?
Name the principle on which a soundboard works.
What is the shape of a soundboard kept behind the speaker on the stage of a big hall ?
Draw a labelled diagram to show the multiple reflections of sound in a part of the stethoscope tube.
Explain how is the principle of echo used by
(a) The bat during its flight at night,
(b) The dolphin to locate small fish as its prey.
What are mechanical waves?
Draw a diagram representing a wave of amplitude 4 cm and wavelength 2 m. If the frequency of the wave is 150 Hz, calculate its velocity.
(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?
What is meant by an echo? Explain.
