Question

In SONAR, we use

• A. ultrasonic waves
• B. infrasonic waves
• C. radio waves
• D. audible sound waves

Answer 1

The correct option is A

ultrasonic waves

Explanation for Correct Option:

Option (A): ultrasonic waves

1. The SONAR is an acronym for ‘Sound Navigation and Ranging’ and is employed for underwater detection, ranging, and depth measurement.
2. Due to the high attenuation of electromagnetic waves in seawater, radio communication between submerged submarines in a sea is not possible.
3. Since the attenuation of sound waves in water is low, ultrasonic waves are used for underwater communication.
4. The waves above the higher audibility limit or $20kHz$ are called ultrasonic waves.
5. Hence, in SONAR we use ultrasonic waves.

Explanation for Incorrect Option:

Option (B): infrasonic waves

1. The waves below the lower audibility limit or $20Hz$ are called infrasonic waves.
2. They do not have enough energy to penetrate the depths of seawater.
3. Hence, in SONAR, we do not use infrasonic waves.

Option (C): radio waves

1. Radio waves are electromagnetic waves.
2. Due to the high attenuation of electromagnetic waves in seawater, radio communication between submerged submarines in a sea is not possible.
3. Hence, in SONAR, we do not use radio waves.

Option (D): audible sound waves

1. The waves in the range $20Hz-20kHz$ are called audible sound waves.
2. They do not have enough energy to penetrate the depths of seawater.
3. Hence, in SONAR, we do not use audible sound waves.