Question

Name the waves which are used in 'SONAR' to find the depth of a sea. State one property of waves for their use.

Answer 1

SONAR uses sonic waves (sound). Typically, sonar use sounds with frequencies inaudible to human ear.
Actually, sonar uses a wide range of frequencies. Very low frequencies (100 Hz to 1 kHz) are used for long range detection and deep sea floor sounding. Mid-range frequencies (1 kHz to 10 kHz) are used for target identification. Ultrasonic frequencies (50 kHz and up) are used in navigation and commercial sonar devices like fish finders.
Properties of Ultrasonic waves:

• They produce heating effect when passes through the medium.
• They get reflected, refracted and absorbed by the medium similar to the ordinary sound waves.
• They act as catalytic agents to accelerate chemical reactions.
• They produce stationary wave pattern in the liquid while passing through it.