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

Hint: 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.

Complete step by step answer:

The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extremely high (ultrasonic). 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:
1. Ultrasonic waves are high-frequency waves that have a heating effect.
2. They also have smaller wavelength than all the other waves
3. The ultrasonic waves are reflected and refracted just like light waves.
4. The ultrasonic waves cannot travel through a vacuum.
5. They act as catalytic agents to accelerate chemical reactions.
6. They produce stationary wave patterns in the liquid while passing through it.

Note:
A sonar device sends pulses of sound waves down through the water. When these pulses hit objects like fish, vegetation, or the bottom, they are reflected back to the surface. The sonar device measures how long it takes for the sound wave to travel down, hit an object, and then bounce back up.