Sound Navigation and Ranging (SONAR) is used to detect underwater objects. For this, its transmitter produces
ultrasonic waves
SONAR works on the principle of echo-ranging: the transmitter sends out sound pulses that travel through water, reflect off an underwater object, and are picked up by a receiver, and the time delay is used to calculate the object's distance.
Since these sound pulses must have a frequency far above the range of human hearing (above about 20 kHz) to give sharp, focused beams and better resolution underwater, the transmitter produces ultrasonic waves rather than microwaves, visible light or infrared, which do not travel efficiently through water for this purpose.
Hence, the answer is ultrasonic waves.
Important Questions from Wave
Which one of the following statements is true for sound waves propa- gating in air?
Which one of the following optical phenomena supports that the light is a transverse wave?
Which of the following is the horizontal distance between two successive crests?
Which of the following statements is correct?
What is the correct order of radiations in descending order of frequencies?
