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प्रश्न
Define the following terms : (a) Echolocation (b) Echocardiography, and (c) Ultrasonography.
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उत्तर
(i) Echolocation: It is the method used by some animals to locate the objects by hearing the echoes of their ultrasonic squeaks. This method is used by bats and dolphins in finding their way and detecting their prey.
(ii) Echocardiography is a method used to investigate the action of the heart by using ultrasound waves.
(iii) Ultrasonography is a technique of obtaining pictures of internal organs of the body by using echoes of ultrasound pulses.
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संबंधित प्रश्न
Explain how bats use ultrasound to catch a prey.
Explain the working and application of a sonar.
A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.
What name is given to sound waves of frequencies higher than 20 kHz ?
Draw labelled diagrams to represent (a) soft sound, and (b) loud sound, of the same frequency.
Explain the term 'pitch' of a sound. On what factor does the 'pitch' of a sound depend ?
Draw labelled diagrams to represent sound of (a) low pitch, and (b) high pitch, of the same loudness.
Give one use of ultrasound in industry and one in hospitals.
Explain how, flaws (or defects) in a metal block can be detected by using ultrasound.
A sonar station picks up a return signal after 3 seconds. How far away is the object ? (Speed of sound in water = 1440 m/s).
