Which one of the following instruments is used for locating submerged objects in an ocean?

Q. Which one of the following instruments is used for locating submerged objects in an ocean?

1. Audiometer
2. Galvanometer
3. Sextant
4. SONAR

Answer: SONAR

SONAR [Sound Navigation and Ranging] is used for locating submerged objects in an ocean. It is based on a very simple principle i.e. pulse of ultrasonic waves is sent into the water, it strikes the target and bounced back towards the source. It helps to detect or locate submerged submarines and icebergs.

Sonar is a machine that uses underwater sound waves to find other objects in the sea. A sonar can work by sending out sound and listening for echoes (active sonar), like a radar, or by listening for sound made by the object it is trying to find (passive sonar).

The basic parts of an active sonar are:

1. the transmitter creates the sound waves.
2. the hydrophone or hydrophone array converts the sound waves into electricity.

The first use of passive sonar was in 1490 by Leonardo da Vinci, when he put a tube onto water and listened. Active sonar was first used in 1917 by Paul Langevin. The word SONAR was created during the Second World War as an acronym for Sound Navigation and Ranging. This acronym replaced the British acronym ASDIC. The word is now thought by many people as a regular word, no longer as an acronym.

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Q. SONAR is mostly used by—

1. Astronauts
2. Engineers
3. Doctors
4. Navigators

Answer: Navigators

SOANR is mostly used by navigators.

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Q. In SONAR, we use—

1. Radio waves
2. Ultrasonic waves
3. Audible sound waves
4. Infrasonic waves

Answer: Ultrasonic waves

SONAR Full Form: Sound Navigation and Ranging

Sonar (Sound Navigation Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.
The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extremely high (ultrasonic).