SONAR is a device that is used to measure the distance of underwater o

SONAR is a device that is used to measure the distance of underwater objects by a ship. Which of the following types of waves does it use for this purpose?

[amp_mcq option1=”Infrasonic waves” option2=”Sound waves in audible range for human beings” option3=”Ultrasonic waves” option4=”All of the above” correct=”option3″]

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UPSC NDA-2 – 2022

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SONAR (Sound Navigation and Ranging) systems typically use ultrasonic waves to measure distances and detect underwater objects.

– SONAR works by emitting sound pulses and measuring the time it takes for the echo to return after bouncing off an object.
– The speed of sound in water is known, so the distance can be calculated from the travel time.
– Ultrasonic waves (frequencies above the human hearing range, typically >20 kHz) are preferred in SONAR for several reasons, including better directionality, less attenuation over typical ranges compared to higher frequencies, and superior resolution compared to lower (infrasonic or audible) frequencies for object detection.

SONAR can be active (emitting pulses) or passive (listening to sounds). Active SONAR, used for distance measurement, relies heavily on the properties of ultrasonic pulses. While lower frequencies might be used for long-range detection (where attenuation is lower), ultrasonic frequencies are standard for detailed navigation and object location applications described in the question.

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